Question

X - Y = 4 and xy 21 then the value of x 2 + y 2

Answer 1

xy=21

y=21/x

putting y=21/x

x-21/x=4

x^2-21=4x

x^2-4x-21=0

x^2-7x+3x-21=0

x(x-7)+3(x-7)=0

x=7

y=3

x2+y2

49+9

58