Simplify this expression: 3c + 7 - 9c

-6c + 7

Step-by-step explanation:

To simplify this expression, you must add like terms. Because 3c and -9c both have the same variable (c), they are like terms.

3c + (-9c) = -6c

The 7 stays the same, so the simplified expression is -6c + 7.

Hope this helped :)

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