briandoldan wrote:

Is it Ok to take the roots first?For example, in question 1 the roots for statement 1 are 0 and 5. For statement II, 0 and -5

Data sufficiency

1) Is X=5?

(I) x^2 – 5x = 0

(II)2x^2 + 10x= 0

2) Is x = y?

(I) |x-2|= 5

(II) y^2 – 4y – 21=0

I'm not sure that I understand your question... But as for the problems:

Is x=5?

(1)

x^2-5x=0 -->

x=0 OR x=5. Not sufficient, to answer whether

x=5.

(2)

2x^2+10x=0 -->

x=0 OR x=-5. Here we know that

x\neq{5}, hence sufficient.

Answer: B.

Is x = y?(1)

|x-2|= 5. Clearly insufficient as no info about

y. But from this statement we know that either

x=7 or

x=-3.

(2)

y^2-4y-21=0. Clearly insufficient as no info about

x. But from this statement we know that either

y=7 or

y=-3.

(1)+(2) Now, it's possible that

both x and

y equal to -3 (or 7) and in this case answer would be YES:

x=y BUT it's also possible

x to be -3 and

y to be 7 (or vise-versa) and in this case answer would be NO:

x\neq{y}. Two different answers to the question, hence not sufficient.

Answer: E.

Hope it helps.

Thanks a lot Bunuel. It helped a lot. =)