Question 194045
 please multiply and simplify

(4a-5)(2a^2+a-4)
= 4a*(2a^2+a-4) - 5*(2a^2+a-4)
= {{{8a^3 + 4a^2 - 16a - 10a^2 - 5a + 20}}}
= {{{8a^3 - 6a^2 - 21a + 20}}}