8-9x=15x+7+3x
show how you get x

Simplify 15x + 7 + 3x to 18x + 7

8 - 9x = 18x + 7

Add 9x to both sides

8 = 18x + 7 + 9x

Simplify 18x + 7 + 9x to 27x to 7

8 = 27x + 7

Subtract 7 from both sides

8 - 7 = 27x

Simplify 8 - 7 to 1

1 = 27x

Divide both sides by 27

1/27 = x

Switch sides

x = 1/27

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb