Question 1030143
{{{(x^3 - 4x^2 + 2x - 5)(x^2 + tx - 7) = x^5 +(t-4)x^4 +(-4t-5)x^3 + (2t+23)x^2 + (-5t-4)x +35}}} after expansion. (Use the vertical method for faster result :D!)

Since the outcome is supposed not to have {{{x^2}}}, ==> 2t + 23 = 0, or {{{t = -23/2}}}.