Question

x+y=5 x la pătrat + y la pătrat =15
a=(x-y)+(x+y) la pătrat +(x+y) la a treia a=?

Answer 1

x+y=5 | ()²
x²+2xy+y²=25
15+2xy=25⇒ 2xy=10

(x-y)²= x²-2xy+y²=15-10=5 
(x-y)²=5⇒ x-y=√5

a=(x-y)+(x+y)²+(x+y)³
a=√5+25+125=150+√5