For what value of b a polynomial in standard form, equivalent to the product of (x2–10x+6)(2x+b): b has equal coefficients for x3 and for x

Answer 1

Multiply out the given trinomial by the binomial to ge

2x³ + (b-20)x² + (12-10b)x + b²

Then 12 - 10b = 2.

You should be able to finish from here.