Maths

X^2-xk-8x+8k=x^2-5kx+m
x(-k-8)=-5kx
-k-8=-5k
-8=-4k
K=2
8(2)=m
16=m

If a and b are +ve integers and a^2-b^2 =7,what is the value of a ?

A) 3
B) 4
C) 5
D) 6
E) 7

a = 4, b = 3 --> answer choice A.

To solve it without guesswork, factor the LHS to (a-b)(a+b) = 7. a+b is a positive integer, so a-b is also a positive integer. 7 factors to 1*7 only, and you can show that a = 4, b = 3 is the only solution.

Everything is correct except your answer choice. B is the answer

^whoops, I meant B.

Haha, it was a minuscule mistake. First time I see that from you.