Which expression is eqivalent to (x^2-3x)(4x^2+2x-9)

For this case we must find an expression equivalent to:

We apply distributive property, term by term, taking into account that:

By definition we have to, to multiply powers of the same base, the same base is placed and the exponents are added:

We add similar terms taking into account that:

Equal signs are added and the same sign is placed.

Different signs are subtracted and the major sign is placed.

An equivalent expression is: