Question

How do you solve `21= | y + 685| + 6`?

Answer 1

`y=-670`

Explanation:

Since everything inside of the absolute value bars (`|y+685|`) is already positive there is no need for them anymore:
`21=y+685+6`
Next add:
`21=y+691`
Then subtract:
`y=-670`
Check by putting it back in:
`21=|-670+685|+6`
Solve absolute value bars first:
`21=|15|+6`
Then Solve:
`21=21`
Works