Elitmus
Exam
Numerical Ability
Number System
c consists of only non negative numbers in the given equation x^2 - 7x + c =0 how many rational roots occurs
a.) 1 b.) 4 c.) 6 d.) infinite
Read Solution (Total 20)
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- in question something is missing that is c is also real non negative numberd 49-4c for finding the value of roots of this equation (49-4c)^1/2 has to rational integerso only c=0,6,10,12 hence b)4 is correct answer.
- 10 years agoHelpfull: Yes(24) No(3)
- ans is d.
- 10 years agoHelpfull: Yes(16) No(3)
- In question they are asking only how many rational roots and c consists only non negative numbers means whole no.s . So for c=0 , the equation has 2 roots and for c=1 there will be 2 roots and for c=2 there will be 2 roots and for c=3 there will be 2 roots and so on.
so the equation has infinite roots - 10 years agoHelpfull: Yes(5) No(5)
- for rational root D=perfect squre here D=49-4c and also we cant take c(-ve)a/c to question so possible value of c for which root is rational is C=0,6,10,12
WHERE D=b*b-4ac - 10 years agoHelpfull: Yes(5) No(0)
- This question was asked in yesterday elitmus test .... one of the simplest
question - 10 years agoHelpfull: Yes(3) No(5)
- ans is infinite
- 10 years agoHelpfull: Yes(2) No(1)
- b) 4 is the answer. Vikash is correct. I got this question yesterday in litmus.
- 9 years agoHelpfull: Yes(2) No(0)
- c) 6 rational roots possible
- 10 years agoHelpfull: Yes(1) No(3)
- (49-4c)^1/2
put c=0,6,10,12 we get 2 rational roots distinct each time.
so total is 8 roots.Pravena please dont give incomplete choices.
- 10 years agoHelpfull: Yes(1) No(2)
- there was no option as 8....
- 10 years agoHelpfull: Yes(1) No(0)
- for rational roots D >=0;
(49-4c)^1/2>=0;
so probable value of c={0,1,2,3,4,5,6,7,8,9,10,11,12}
substituting these value of c one by one we will see at c={0,6,10.12}
condition gets full fill...so
Ans should be (b). - 9 years agoHelpfull: Yes(1) No(0)
- C is the answer
Put c=6,10,12
The roots are 1,6,2,5,3 and 4 - 10 years agoHelpfull: Yes(0) No(4)
- Can anyone explain me why it is infinite
- 10 years agoHelpfull: Yes(0) No(1)
- in question something is missingthat isc is also real non negative numberd49-4c for finding the value of roots of this equation49-4c12 has to rational integerso only c061012hence b4 is answer
- 10 years agoHelpfull: Yes(0) No(0)
- @ Amit Anand The choices r not incomplete...
- 10 years agoHelpfull: Yes(0) No(0)
- option b is right
- 10 years agoHelpfull: Yes(0) No(0)
- there should be an additional information regarding c that what type of value shoul it take if it can take +ve real no. then answer should be 8 as c can take values : 0,6,10,12 all together which gives 8 roots otherwise answer will be d infinite
- 10 years agoHelpfull: Yes(0) No(0)
- option d is correct
- 10 years agoHelpfull: Yes(0) No(1)
- 49-4*1*c>=0
=>c - 10 years agoHelpfull: Yes(0) No(0)
- there will be total of 4 value of c i.e., c=0,6,10,12 which will give rational roots
as roots= (7+-(49-4c)^1/2) /2 should be rational. - 10 years agoHelpfull: Yes(0) No(0)
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