Question 127364
Just replace x with -3 and see if P(-3)=0
P(x) = 8x^3 + 9x^2 + x + 138
P(-3) = 8*(-3)^3 + 9*(-3)^2 -3 + 138
=8*-27+9*9-3+138
=-216+81-3+138
=0
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Yes -3 is a zero of P(x)
.
Ed