Question

Solve 56x + x^3 = 15x^2 by factoring

Answer 1

Wouldn't it be x(56+x^2) = (I don't know the rest)

Answer 2

i think i got it:
x(56+x^2)=15x
divide by x both sides
so:
x(56+x^2)/x=15x/x
then you get 56+x^2=15x
arrange:i.e
x^2-15x+56=0
1*56=56
-8+-7=-15
insert:x^2-8x-7x+56=0
x is common....
x(x-8)......-7(x-8)=0
(x-7)...(x-8)=0
since (x-7)=0
x=7
since (x-8)=0
x=8
possible values of x are: 8 & 7

Answer 3

sorry the division part is suppposed to be: x(56+x^2)=15x^2
then divide by x both sides you get: 56+x^2=15x
the rest is ok