Question

daca x+y=5 si x²-y²=15 , calculati valoarea numarului a=(x-y)+(x-y)²

Answer 1

x+y=5
$x^{2} -y^{2} =15 \\ x^{2} - y^{2} =(x-y)*(x+y) \\ 5*(x+y)=15 \\ x-y=3 \\ a=(x-y)+ (x-y)^{2} \\ a=3+ 3^{2} \\ a=12$

Answer 2

x+y=5
x²-y²=15⇒(x-y)(x+y)=15, inlocuim⇒5(x-y)=15⇒⇒⇒x-y=15/5⇒x-y=3
a=(x-y)+(x-y)²=3+3²=3+9=12