You have the following equation:
(w + 5)/(-3) = (-2w + 6)/(4)
In order to solve the previous equation for w, you proceed as follow:
(w + 5)/(-3) = (-2w + 6)/(4)
you multiply by the least common multiple of 3 and 4 both sides, in order to cancel out the denominators both sides. The least common multiple of 3 and 4 is 12, then, you have:
(12)(w + 5)/(-3) = (12)(-2w + 6)/(4) divide coefficients both sides
-4(w + 5) = 3(-2w + 6) apply distribution property both sides
-4w - 20 = -6w + 18 add 6w and 20 both sides
-4w + 6w = 18 + 20 simplify like terms
2w = 38 divide by 2 both sides
w = 38/2
w = 19
Hence, the solution to the given equation is w = 19