Question

if x2 y2 =34 and xy=10 Divide[1,2 ]. find the value of 2(x+y)2 + (x-y)2

Answer 1

Answer:

x^2—y^2=16…(1)

x^2+y^2=34..(2)

Add both the equation to get

2x^2=50

x^2=50/2=25

Taking square root x=—5 or 5

Plug x^2=25 in equation (2)

y^2=9

Taking square root

y=—3 or 3

xy=5*3=15(when both x,y are positive)

xy=(—5)(—3)=15..(when both x and y are negative)

xy=5(—3)=—15..(x is positive,y is negative)

xy=(—5)(3)=—15..( x is negative,y is positive)

Answer: xy=15 or xy=—15