Question

Daca x-y=3 si x2-y2=12,determinati nr.
a=(x+y)+(x+y)2+(x+y)3
Unde am pus 2 sau 3 este la a doua respectiv la a treia.

Answer 1

x-y=3
x=3+y
x² -y ²=12
(x-y)(x+y)=12
(3+y-y)(3+y+y)=12
3(3+2y)=12
9+6y=12
6y=12-9
6y=3
y=3/6
y=1/3
x-y=3
x- 1/3=3
x=3+1/3
x=3intreg 1/3
x=10/3
10/3-1/3=9/3=3
a=10/3+1/3+(10/3+1/3)²+(10/3+1/3)³=11/3+(11/3)²+(11/3)³=11/3+121/9+1331/81=
297+968+1331/81=2596/81