The remainder when p(x) is divided by (x+2) is; -79.
Since one of it's factors is (x+1), it follows that P(-1) = 0.
Hence; 0 = (-1)³ -4(-1)² -a +20
a = 15.
Hence, the polynomial is; p(x)=x3−4x2+15x+20
The remainder when p(x) is divided by (x+2) is;
p(-2) = (-2)³ -4(-2)² + 15(-5) +20
p(-2) = -8 -16 -75 +20
p(-2) = -79.
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