Question

Find t if the expansion of the product of x^3-4x^2+2x-5 and x^2+tx-7 has no x^2 term.

Answer 1

(-4x^2)(-7) + (2x)(tx) + (-5)(x^2)
= x^2(28+2t-5)

so, you need 28+2t-5 = 0