Question

xy (x+y)=3
x^3+y^3=8 ---> (x+y)^3 =?

Answer 1

try expanding \((x+y)^3\) - you should get a clue from that

Answer 2

i try but i dont understand

Answer 3

what do you get when you expand that?

Answer 4

= (x+y) ( x^2 - xy + y^2)

Answer 5

that is not correct - there should not be a mius sign there

Answer 6

\[(x+y)^3=(x+y)(x+y)(x+y)=(x+y)(...)\]

Answer 7

you need to replace the ... with the expansion of this: \((x+y)(x+y)=?\)

Answer 8

you can break this up as follows:\[(x+y)(x+y)=x(x+y)+y(x+y)=?\]

Answer 9

I am not understanding

Answer 10

expand the last expression I typed above, i.e.:\[(x+y)(x+y)=x(x+y)+y(x+y)=?\]

Answer 11

this comes from: