+128474 a.) x^3 + 3x^2 - x = 3
Subtract 3 from both sides
x^3 + 3x^2 - x - 3 = 0
Factor by grouping
x^2 (x + 3) - 1(x + 3) = 0
(x^2 - 1) ( x + 3) = 0
(x + 1) ( x - 1) ( x + 3) = 0
Setting each factor to 0 and solving for x produces
x = -1 or x = 1 or x = -3
b.) b^3 - 4b^2 -21b = 0
Factor as
b ( b^2 - 4b - 21) = 0
b (b - 7) ( b + 3) = 0
Setting each factor to 0 and solving for b produces
b = 0 or b = 7 or b = -3
