Question

If ? A² + b² = 7b and b² + (2b-a) ²= 7², what is (a - b) ²?

Answer 1

7^2+2ab - 4b^2

Explanation:

A² + b² = 7b

b² + (2b-a) ²= 7²

FOIL

b^2 +4b^2-4ba+a^2= 7^2

Rewriting

a^2 -2ab + b^2 +4b^2 -2ab = 7^2

Add 2ab and subtract 4b^2 from each side

a^2 -2ab + b^2 +4b^2 - 4b^2 -2ab+2ab = 7^2+2ab - 4b^2

a^2 -2ab + b^2 = 7^2+2ab - 4b^2

(a-b)^2 = 7^2+2ab - 4b^2