Question

How do you combine like terms in `78m - 8( 9+ 5m ) + 30`?

Answer 1

Expand the terms in parenthesis, group like terms and then combine the like terms. See full process below.

Explanation:

First, we will expand the terms in parenthesis, being sure to pay special attention to the signs:

`78m - 8(9 + 5m) + 30 ->`

`78m color(red)(-) 72 color(red)(-) 40m + 30`

Now we can group the like terms:

`78m color(red)(-) 40m color(red)(-) 72 + 30`

And now we can combine the like terms:

`(78 color(red)(-) 40)m color(red)(-) 42`

`38m color(red)(-) 42`