Please help I have a timed test will give brainiest ;-;
Which equation, when solved, results in a different value of x than the other three?
-7/8 7 x-3/4=20
3/4+7/8x-20
-7(1/8)x-3/4=20
-7/8(-8/7)x-3/4=20(-8/7)

5

step-by-step explanation:

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