Question

12a-7b-(4a-21b)

Answer 1

if you distribute the minus sign you get
\[12a-7b-(4a-21b)=12a-7b-4a+21b\]
then you can combine like terms

Answer 2

12a-7b-(4a-21b)
12a-7b-4a+21b
a(12-4)+b(21-7)
8a+14b

Answer 3

Thanks trying to study and freshen up on some things!

Answer 4

\[12a-7b-4a+21b\] you can probably do in your head with not much practice
think " twelve minus four is eight"
"twenty one minus seven is fourteen"
gives \(8a+14b\)

Answer 5

got it thanks :)

Answer 6

the parenthesis threw me off didnt know if it made it negative or not..