Question

-3 (12-m) = -1 (m-8)

Answer 1

First, rewrite the equation, separating the terms inside the parentheses and multiplying each by the term preceding the parenthesis, remembering that the product of two negatives is a positive, and likewise (later) with quotients:

(-3 * 12) + (-3 * (-m)) = (-1 * m) + (-1 * (-8))

-36 + 3m = -m + 8

Subtract 8 from both sides:

(-36 - 8) + 3m = -m + (8 - 8)
-44 + 3m = -m

Divide each term by -m:

(-44 / (-m)) + (3m / (-m)) = -m / (-m)
(44 / m) - 3 = 1

Add 3 to both sides:

(44 / m) - 3 + 3 = 1 + 3
44 / m = 4
(is the answer jumping out at you yet?) :-)

Multiply both sides by m:

(44 / m) * m = 4m
44 = 4m

Divide both sides by 4:

44 / 4 = m
11 = m

Verify by substituting for m in the original equation:

-3(12 - m) = -1(m - 8)
-3(12 - 11) = -1(11 - 8)
-3(1) = -1(3)
-3 = -3

Voila! That's it!