Question

(a) If (x + y) 2 =81 and xy = 4 then find the value of x
2 + y2

Answer 1

Answer:

x²+y²=73

Step-by-step explanation:

take (a+b)²=a²+b²+2ab

(x+y)²=x²+y²+2xy

substitute

(x+y)²=81 ;and xy=4

81=x²+y²+2×4

x²+y²=81-8

x²+y²=73