Data Sufficiency

Hello guys,

I was wondering if someone could tell me why exactly fact 1 in this DS question is sufficient.

When I came across it, I thought that replacing "x(squared) + 6x" in the question statement to '40' seemed to obvious. What if the question statement stated "x(squared) + 6x = -9" I basically didn't do this move (subtracted 9 from both sides) because I thought it was too easy/good to be true.

What's the value of x(squared) + 6x + 9 ?

Fact 1) x(squared) + 6x = 40
Fact 2) x + 3 = 7

I hope I made my question clear.

Thanks a lot for your help and time.
Cheers,
Diego

diegocml wrote:What's the value of x² + 6x + 9?

(1) x² + 6x = 40

(2) x + 3 = 7

Statement 1:

Given that x² + 6x = 40, we can substitute 40 into the expression from the question.

40 + 9 = 49

Sufficient.

Statement 2:

x² + 6x + 9 = (x + 3)²

Since statement 2 provides the value of x + 3, we can calculate the value of x² + 6x + 9.

Sufficient.

The correct answer is D.