Question

Detailed answers appreciated: (7a -4) (2a -5)

Answer 1

Expand the expression?

Perform indicated multiplication:

7a(2a)+7a(-5)-4(2a)-4(-5)

14a^2-35a-8a+20  combine like terms, ie (-35a-8a)=-43a

14a^2-43a+20

Answer 2

1. Us the FOIL method: (a + b)(c + d) = ac + ad + bc + bd:
14a^2 - 35a - 8a + 20
2. Collect like terms:
14a^2 + (-35a - 8a) + 20
3. Simplify:
14a^2 - 43a + 20