Question

How do you factor `3ab-15ac+4bd-20cd`?

Answer 1

`(3a+4d)(b-5c)`

Explanation:

`\color(red)(3ab-15ac)+4bd-20cd = color(red)(3a(b-5c)) + 4d(b-5c)`
`qquad = (color(red)(3a)+4d)(b-5c)`