If 3^x - 3^(x-1) = 18, then the value of x^x is

M4maths Previous Puzzles

15 Jul 2014 Solve If 3^x - 3^(x-1) = 18, then the value of x^x is: OPtion
1) 3
2) 18
3) 8
4) 19
5) 27
6) 36
7) 216
8) 81
9) 64
10)None of these; Correct Option: 5 Best Solution (76)

Sundar Kumar 10 years AGO

3^x - 3^(x-1) = 18
3^x-3^x.3^-1=18
3^x(1-1/3)=18
3^x=18*3/2
3^x=27
3^x=3^3
here x=3
then , x^x=3^3=27
Answer: option 5) 27

Like? Yes (77) | No (18)

Sourojit Dhua 10 years AGO

3^3- 3^(3-1) = 18
therefore,
3^3=27

Like? Yes (94) | No (79)

nigarashraf 10 years AGO

3^x(2/3)=18
x=3
x^x=3^3=27

Like? Yes (22) | No (17)

SUMIT 10 years AGO

3^x-1(3-1)=18
so,3^x-1=9
x=3
so x^x=27

Like? Yes (6) | No (2)

priyanka 10 years AGO

3^x-3^x/3=3^x(1-1/3)=18
3^x(2/3)=18
x=3
x^x=3^3=27

Like? Yes (7) | No (4)

Sandeep singh 10 years AGO

3^3=27, 3^(3-1)=9. 27-9=18
Therefore x=3
Now 3^3=27

Like? Yes (6) | No (3)

Arpan Bhattacharyya 10 years AGO

3^x=3^3
x=3
again x^x=3^3
=27

Like? Yes (6) | No (4)

sompon temtheerakij 10 years AGO

3^x - 3^x-1 = 18
3^3 - 3^3-1 = 18
x = 3
x^x = 3^3 = 27

Like? Yes (3) | No (1)

devmitra 10 years AGO

3^x(1-1/3)=18
=>3^x(2/3)=18
=>3^x=27
=>3^x=3^3
=>x=3=>3^3=27...option 5

Like? Yes (3) | No (2)

Ravi Bhalani 10 years AGO

here x=3
so,27-9=18
3^3=27

Like? Yes (4) | No (4)

S M ANIRUDH 10 years AGO

3^x-3^(x-1)=18
Clearly x= 3 satisfies above equation
X^x= 3^3 = 27

Like? Yes (3) | No (3)

Sneha Goel 10 years AGO

solving the equation, we get
3^x=3^3
x=3
hence, x^x=3^3=27

Like? Yes (5) | No (6)

Satyaki 10 years AGO

LET x^3=a
so our equation becomes ,
a-a/3=18
Solving we get, a=27
so. x^3=27 ,
then x=3
so x^x= 3^3 = 27

Like? Yes (4) | No (6)

naina 10 years AGO

put x= 3
3^3-3^(3-1)=18
=>x=3
x^x=3^3=27

Like? Yes (3) | No (5)

monika garg 10 years AGO

3^x(1-(1/3))=18

(3^x)*(2/3)=18

3^x=27

x=3

then x^x=27

Ans = 27

Like? Yes (2) | No (4)

dushyant singh pawar 10 years AGO

Given 3^x-3^(x-1)=18

or 3^x-(3^x/3)=18

or 3*3^x-3^x=18*3=54

or 3^x(3-1)=54

or 3^x=54/2

or 3^x=27

or 3^x=3^3

hence, if bases are same therefore, x=3

hence x^x=3^3=27 [Answer is option 5]

Like? Yes (2) | No (4)

pankaj kumar 10 years AGO

3^x - 3^(x-1) =18
3^(x-1) { 3-1 } =18
3^(x-1) = 18/2 =9 =3^2
x-1 =2
x=3

so x^x = 3^3 =27

Like? Yes (3) | No (5)

KRISHNA CHANDRA UPADHYAY 10 years AGO

let x = 3 then 3^3- 3^2=18 satisfied so we can take x=3 then
x^X=3^3=27

Like? Yes (4) | No (6)

Nilesh Dattatraya Veer 10 years AGO

3^x - 3^(x-1)= 3^x - 3^x/3 = 3^x(1-1/3)=18
3^x *(2/3)=18
3^x=27
x=3
so (x^x)=3^3=27

Like? Yes (2) | No (4)

Soheli Bhaduri 10 years AGO

Ans:5 (27)
3^x-3^x-1=18
3^x-3^x/3=18
3^x[1-1/3]=18
3^x=18*3/2=27=3^3
So,x=3.
x^x=3^3=27.

Like? Yes (3) | No (6)

Grishma Shah 10 years AGO

dividing the given eq by 3^x
resulting to: 2/3 = 18/3^x
hence Solving above 3^x = 27
Therefore X = 3
X^X = 3^3 = 27

Like? Yes (3) | No (6)

S.Rosyponmary 10 years AGO

3^x-3^(x-1)=18
the x value is 3 so 27-9=18;

3^3=27

Like? Yes (1) | No (4)

Abhishek Jana 10 years AGO

3^x-3^(x-1)= (3.3^x-3^x)/3=3^x(3-1)/3=18
3^3=27
x= 3
X^X=27

Like? Yes (1) | No (4)

Barun Kumar 10 years AGO

3^(x-1)*{3-1}=18
3^(x-1)=9
3^(x-1)=3^2
equating the powers
x-1=2
=>x=3
therefore x^x=3^3=27 ans

Like? Yes (1) | No (4)

Subhajit Naskar 10 years AGO

x=3
then x^x = 27

Like? Yes (1) | No (4)

RANJAN KUMAR PANDIT 10 years AGO

3^3-3^(3-1)=18
so x=3
x^x=27

Like? Yes (1) | No (4)

BHANU KUMAR 10 years AGO

let x =3
then 3^x=3^3=27
3^x-1=3^2=9
hence it satisfies the given equation.
so x^x=3^3=27

Like? Yes (3) | No (6)

Brijesh Rawat 10 years AGO

3^3-3^(3-1)=18
3^3=27

Like? Yes (1) | No (4)

Supriyo Dey 10 years AGO

By calculating,x=3 so x^x=27

Like? Yes (1) | No (4)

saurabh gupta 10 years AGO

3^x(1-1/3)=18
3^x=27
x=3
ans=27

Like? Yes (1) | No (4)

Anitha 10 years AGO

On substituting x=3 , the equation is satisfied.. so 3^3=27.
The answer is 27(option 5)

Like? Yes (1) | No (4)

Dr.Dipin Singh 10 years AGO

3^x - 3^(x-1) = 18
let
3^(x-1) = y;
then
3y-y=18
y=9=3^(x-1)=3^2
(x-1)=2
x=3
x^x=3^3=27

Like? Yes (3) | No (6)

Sasikumar 10 years AGO

x= 3
3^3 = 27
3^(3-1) = 9
27 - 9 = 18

x^x = 3^3 = 27

Like? Yes (1) | No (4)

Shaik Riyaz 10 years AGO

Substitute through options...let x=3
After substitute 18 is answer..after that 3 to the power of 3 nothing but 27

Like? Yes (1) | No (4)

Ashish kumar 10 years AGO

3^x = 3^3
x = 3
so, 3^3 = 27

Like? Yes (1) | No (4)

Ankur Tamrakar 10 years AGO

3^x(1-1/3)=18
3^x=(18*3)/2
3^x=27
x=3
x^x=27 So 5)

Like? Yes (1) | No (4)

deepak 10 years AGO

by hit & trail method...
x=3 satisfy this equation
hence x=3;
so, 3^3=27

Like? Yes (1) | No (4)

NITIN KUMAR GOYAL 10 years AGO

X=3

Like? Yes (1) | No (4)

HARMEET KAUR 10 years AGO

If 3^x - 3^(x-1) = 18, then
x=3
the value of x^x =3^3=27

Like? Yes (2) | No (5)

saira fatma 10 years AGO

3^(x-1)[3-1]=3^2.2
=3^(x-1).2=3^2.2
=(x-1)=2

=x=3
x^x=3^3=27

Like? Yes (1) | No (4)

SHANMUGAPRIIYAN 10 years AGO

x is 3
3^3=27-3^(3-1)=18
SO x^x=3^3=27

Like? Yes (2) | No (5)

vishnuvardhan 10 years AGO

let 3^x=y
2y/3=18
y=27
3^x=27
x=3
x^x=3^3=27

Like? Yes (1) | No (4)

Jonibek 10 years AGO

3*3^x-3^x=3*18
3^x(3-1)=54
3^x=27
x=3
x^x=27

Like? Yes (1) | No (4)

juhi 10 years AGO

3^x-1(3-1)=3^2*2
value of x will be equal to 3 then the value of x^x means 3^3 is 27.

Like? Yes (1) | No (4)

Ann Theressa 10 years AGO

3^x - 3^(x-1) = 18
==> x = 3

x^x = 3^3 = 27

Like? Yes (2) | No (6)

RAKESH 10 years AGO

3^x - 3^(x-1) = 18
=> 3^x - 3^x / 3 = 18
=> 2/3 * 3^x = 18
=> 3^x = 27
=> x = 3
=> x^x = 27

Like? Yes (3) | No (7)

Yogesh 10 years AGO

3^x-3^(x-1)=18
3^x(1-1/3)=18
3^x(2/3)=18
3^x=27
3^x=3^3
x=3
x^x=3^3=27

Like? Yes (1) | No (5)

Devendra Marghade 10 years AGO

3^x- 3^(x-1)=18
3^x[1-(1/3)]=18
3^x=27 ,x=3
So x^x= 3^3= 27

Like? Yes (4) | No (8)

V SARATH KUMAR 10 years AGO

On solving the above equation we have x=3 so 3^3=27.27 is the answer

Like? Yes (2) | No (6)

Varunraj Reddy 10 years AGO

3^x-3^(x-1)=18
3^x-3^x.3^-1=18
3^x(1-3^-1)=18
3^x(2/3)=18
3^x=27
x=3
Then x^x=3^3=27

Option 5)

Like? Yes (2) | No (6)

aditya saraswat 10 years AGO

3^x-3^(x-1)=18
3^x(1-1/3)=18
3^x*2/3=18
3^(x-1)=9 => x-1=2
x=3 =>x^x=3^3=27

Like? Yes (1) | No (5)

vinusha reddy 10 years AGO

3^x-3^x/3=18
3^x(1-1/3)=18
3^x=27
3^x=3^3
x=3
then 3^3=27

Like? Yes (2) | No (6)

Shashank Kumar 10 years AGO

3^3=27
3^2=9
27-9=18
so value of x is 3
x^x=3^3=27

Like? Yes (1) | No (5)

Lakshmi Narmada 10 years AGO

3^3-3^(3-1)=27-9=18 hence 3^3=27

Like? Yes (1) | No (5)

suman kumar pan 10 years AGO

the value of x is 3...so 3^3=27

Like? Yes (1) | No (5)

shahin raza 10 years AGO

3^3-3^(3-1)=27-9=18 so x=3,x^x=3^3=27

Like? Yes (1) | No (5)

Ravi Kumar Kodari 10 years AGO

3^x-3^x/3=18
3^x(2/3)=18
x=3
so,x^x=27

Like? Yes (3) | No (7)

Ramesh Sriram 10 years AGO

3^x-3^(x-1)=18
3^x-3^x/3=18
3^x(3-1)=18*3
3^x=18*3/2
3^x=27
3^x=3^3
x=3
x^x=3^3=27

Like? Yes (3) | No (7)

Anish Mathur 10 years AGO

3^(x-(x-1))=18
x=3
3^3=27

Like? Yes (1) | No (5)

sai naveen vanapalli 10 years AGO

x=3
and x^x=27

Like? Yes (1) | No (5)

ATUL KUMAR 10 years AGO

(3^3)-(3^(3-1))=18
3^3=27

Like? Yes (1) | No (5)

ganesh saicharan rao 10 years AGO

3^x(1-1/3)=18
3^x(2/3)=18
3^x-1=9
so x=3
x^x=3^3=27

Like? Yes (1) | No (5)

VENKATESH V C 10 years AGO

3^x-3^(x-1)=18
3^x(3)-3^x=54
3^x(3-1)=54
3^x=27
x=3
so
3^3=27

Like? Yes (1) | No (5)

MRITUNJAY KUMAR 10 years AGO

3^x(1-1/3)=18
x=3.
x^x=3^3=27.
ans-option 5)

Like? Yes (2) | No (6)

rahi 10 years AGO

assume 3^x=z
then
z-z/3=18
=>z=27
so,
3^x=3^3
x=3
x^x=3^3=27

Like? Yes (1) | No (5)

Britto prabhu 10 years AGO

27-9=18

3^3-3^2=18

so,3^3=27

Like? Yes (1) | No (5)

pawan kumar chhipa 10 years AGO

3^x- 3^x*3^-1 =18
3^x(1-1/3) =18
3^x=18*(3/2)
solve it x=3
3^3=27

Like? Yes (1) | No (5)

ravi 10 years AGO

of the options 3^3 is the only one that satisfies x^x
so cross checked with x=3

Like? Yes (1) | No (5)

Aravinth kumar 10 years AGO

=3^3 - 3^(3-1)
=27 - 9
=18
so,
Ans : 3^3=27

Like? Yes (1) | No (5)

Ajay Meena 10 years AGO

Put x=3

Like? Yes (1) | No (5)

Saraswathy 10 years AGO

3^x - 3^(x-1) = 18
3^x - (3^x/3) = 18
3^x ( 1-1/3) = 18
3^x * 2/3 = 3^2 * 2
3^(x-1) = 3^2
x-1 = 2
x = 3
x^x = 3^3 = 27

Ans : 27 (Option 5)

Like? Yes (4) | No (9)

Tark Patel 10 years AGO

-> 3^x - 3^(x-1) = 18
-> 3^x = 3^3
so x=3
Hence x^x = 3^3 =27

Like? Yes (2) | No (7)

mansi garg 10 years AGO

3^x-3^(x-1)=18
3^x(1-3^-1)=18
3^x=18*3/2
3^x=27
x=3
x^x=27

Like? Yes (4) | No (9)

shree 10 years AGO

27777777777777777

Like? Yes (1) | No (6)

abhilash kumar 10 years AGO

3^x-3^(x-1)=18
3^x(1-3^-1)=18
3^x=27
X=3
X^x=27

Like? Yes (2) | No (7)

Saroj kumar 10 years AGO

Given, 3'x-3'(x-1)=18
Or, 3'x-3'x3=18
Or, 3'x(1-1/3)=18
Or, 3'x=18*3/2
Or, 3'x=27
Or, x=3.
So, x'x=3'3=27...

OK

Like? Yes (2) | No (7)

Dimple

India

Punjab

Time: 00:01:33

Points

Maths Quotes

The person who can solve mathematical problems,can lead life easily ,Maths tellu that every problem as solution...we can find number of solutions for one problem ...Aplly it in the life also we can lead our life happily...

swetha

God does not care about our mathematical difficulties; He integrates empirically.

Albert Einstein

Placed User Comments

M4Math helped me a lot.

Vipul Chavan 4 years ago

Thanks m4 maths for helping to get placed in several companies.
I must recommend this website for placement preparations.

yash mittal 5 years ago

If 3^x - 3^(x-1) = 18, then the value of x^x is

M4maths Previous Puzzles

15 Jul 2014 Solve