7y-2y+4+3y=-20
First, you want to combine your 'y' Values.
7y-2y+3y
So subtract 7-2 then add 3. It equals 8
So your final 'y' value Is 8y.
So your new problem is...8y+4=-20
Now you get the 'y' alone and the first step to that is to subtract the 4 on BOTH sides.
8y+4=-20
-4 -4
Now your problem is 8y=-24
Step two to getting the 'y' alone is to divide by 8. So...
8y=-24
/8 /8
y=-3
So there you go. Hope I helped.
