Question

x + y = 8 and xy = 15 find
4x^2 + 4y^2

Answer 1

Please see the attachment

Answer 2

Given -

x + y = 8

xy = 15

To find -

4x² + 4y²

Solution -

4x² + 4y²

= 4(x² + y²)

= 4[(x + y)² - 2xy]

{As x² + y² = (x + y)² - 2xy}

= 4[(8)² - 2(15)]

= 4(64 - 30)

= 4*34

= 136