Find t if the expansion of the product of 2x^3 + x^2 - 3x + 5 and x^4 - 7x^3 + tx^2 - 11x + 15 has no x^2 term.
The x^2 terms will consist of
15x^2
(-3x)(-11x) = 33x^2
5tx^2
So
33 + 15 + 5t = 0
48 + 5t = 0
5t = - 48
t = -48/5
+506 
