Question

se x-y=7 e xy=60, então o valor da expressão x²+y² é?

obs: sem bashkara​

Answer 1

(x-y)² = x²+y² -2.xy

( 7 )² = x²+y² -2.(60)

49 = x²+y² -120

49 +120 = x²+y²

x²+y² = 169 ✓

Answer 2

x²+y²=(x-y)²+2xy

x²+y²=7²+2.60=49+120=169