Question

How do you solve `10(1+3b)=-20`?

Answer 1

`b=-1/3`

Explanation:

divide both sides by 10
`=>` `1+3b=-2`

add 1 to both sides
`=>` `3b=-1`

divide both sides by 3
`=>` `b=-1/3`

There is an alternative way, by multiplying out the bracket
`=>` `10+30b=-20`
add 10 to both sides
`=>` `30b=10`
Divide both sides by 30
`=>` `b=-1/3`