given xy = 4 and x^2 + y^2=a, which exspression is equal to (x+y) ^2? A: a+6 B: a+4 C: a+8 D: a

Corretct answer is C: a+8

Step-by-step explanation:

Given xy=4 and x∧2+y∧2=a

The square of the binomial is

(x+y) ∧2 = x∧2 + 2xy + y∧2

when we rearrange this equation we get:

(x+y) ∧2 = (x∧2 + y∧2) + 2 (xy) = a + 2 · 4 = a + 8

God with you!