Question 939079
y=x^3+4x^2;  y=3x+18
y=x^3+4x^2 = 3x+18
f(x) = x^3 + 4x^2 - 3x - 18 = 0
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Try the factors of 18, + and minus.
eg, f(1) = 1 + 4 - 3 - 18 = -16  Not a zero.
Find any real integer zeroes then divide by (x - zero).  One zero will reduce it to a quadratic.