Question

if x square+y square=13 and xy=6 find the value of x+y,x-y,x to the power 4+y to the power 4

Answer 1

[tex] x^{2} + y^{2} = 13 \\ and \\ xy = 6 \\ x^{2} + y^{2}+2xy = 13 + 12 = 25 = (x+y)^{2} \implies x+y = \pm 5 \\ \\ x^{2} + y^{2}-2xy = 13-12 = 1 = (x-y)^{2} \implies x-y = \pm 1[/tex]