Hey Emilyy101!
The answer to your question would be
Y= -18
This is because 3x20 is 60
so then it would be 60 + 3x5y= -30
it has to be a negative number because 60 is greater than -30
then you would add the absolute values which would be 60+30=90
And divide that by 5 which is 18, but then you have to add back on the negative sign.
