Algebra Math Problem?

Question

Can you please help me? "Multiply and simplify:" 6z(3z+7)(z-5)

Answer 1

6z*(3z+7)*(z-5)

Distribute first two terms using distributive property a(b+c) = ab+ac

(6z(3z) + 6z(7))*(z - 5)

(18z^2 + 42z)*(z - 5)

Again distribute terms using the formula (a+b)(c+d) = ac + ad + bc +bd

18z^2(z) +18z^2(-5) +42z(z) +42z(-5)

The product of two different sings is negative

18z^3 - 90z^2 + 42z^2 - 210z

18z^3 - 48z^2 -210z