If one root of quadratic equation 3x^2+px+4=0 is 2/3, other root is..

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11 Apr 2013 quadratic

If one root of quadratic equation 3x^2+px+4=0 is 2/3, other root is..

OPtion

1) 2
2) 3/2
3) 4
4) 6
5) 8
6) 4/3
7) 3/4
8) 10
9) 12
10) None of these

Solution

put 2/3 in given equation and find the value of p
and value of p put in given equation
solve the equation and find two roots
one root 2/3 and other 2
option 1

Correct Option: 1 Best Solution (15)

prashant thakur   11 years AGO

here product of roots=c\a=4/3
so other root=(4\3)*(3\2)=2

Like? Yes (13) | No (6)  

SANTHANAM   11 years AGO

3x^2+px+4=0;
if x=2/3 then;
p=-8;
3x^2-8x+4=0;
x=2/3 and x=2;

Like? Yes (4) | No   

Suresh Busannagari   11 years AGO

Substitute 2/3 value in place of X, then u will get P value then find the roots....

Like? Yes (6) | No (4)  

sumit kumar    11 years AGO

product of root =4/3
1st root =2/3
required root =(4/3)*(3/2)=2

Like? Yes (1) | No   

sanjay singh   11 years AGO

let other root =b
product of roots , 2/3*b=4/3
so, b=4/3*2/3=2

Like? Yes (1) | No   

Dr.Dipin Singh   11 years AGO

In quadratic equation 3x^2+px+4=0 ,
Product of roots= 4/3
one root = 2/3
other root = (4/3)/(2/3)=2 .. option 1

Like? Yes (4) | No (4)  

G REDDI SAI AKHIL   11 years AGO

by putting root in the equation we get p=-8
then sub p value in the equation
we get the roots x=2/3 and x=2

Like? Yes (3) | No (4)  

Ankit Pandey   11 years AGO

first find the value of p, p=-8 and then solve the quadratic equation,
3x^2-8x+4=0.
On solving,
we get x=2 and x=2/3.

Like? Yes (2) | No (3)  

Balakrishnan M   11 years AGO

If one root of quadratic equation 3x^2+px+4=0 is 2/3
i.e., one of the factor is(3x-2)
then consider the another factor is (x-a)
==> (3x-2)(x-a)=3x^2+px+4
Equating the coefficients of x and constant term,
2a=4 ==>a=2,
-3a-2=p ==> p=-8
the given equation is 3x^2-8x+4=0
and other root is x=2

Like? Yes (4) | No (5)  

sainath   11 years AGO

3x^2+px+4=0 and given x=2/3
3(2/3)^2+p(2/3)+4=0
3(4/9)+(2p/3)+4=0
(4/3)+4+(2p/3)=0
(16/3)+(2p/3)=0
16+2p=0
p=-8

so equation is 3x^2-8x+4=0
3x^2-6x-2x+4=0
3x(x-2)-2(x-2)=0
(x-2)(3x-2)=0
=>x= 2 or 3/2
so the 2nd root is 2...

Like? Yes (3) | No (5)  

TARUN   11 years AGO

by putting 2/3 value of p is -8
then u can easily find out other root that is 2

Like? Yes (1) | No (3)  

jitendra singh   11 years AGO

put x=2/3 in eqn. find p then x1+x2=-b/a

Like? Yes (2) | No (4)  

Vinay Sipani    11 years AGO

product of roots = c/a

=> (2/3)*(x) = 4/3
=> x = 2

Like? Yes (2) | No (5)  

Rats   11 years AGO

3x^2+px+4=0 one root is 2/3
So putting x=2/3
we got p=-8
So eq changes to 3x^2-8x+4=0
On solving we get x=2/3,2
So other root is 2

Like? Yes (2) | No (5)  

Darpankumar   11 years AGO

on putting the 1 root in eqution we will get value of p whichwill be -8
and the equation will be 3x^2-8x+4
on solving the roots will be 2,/3.

Like? Yes (2) | No (5)