Question

If x -y is equal to 13 and X y is equal to - 5 then find the value of 1 / 3 X square + y square

Answer 1

Answer

x-y=13. (1)

xy=-5. (2)

Find

1/3(x^2+y^2)=? (3)

Taking square on both side of eq1

(x-y)^2=13^2

x^2+y^2 - 2xy=169

x^2+ y^2 - 2(-5)=169. xy=-5

x^2+y^2+10=169

x^2+y^2=169-10

x^2+y2=159

Put it in eq3

1/3(159)=53

So

1/3(x^2+y^2)=53