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In an equation the Left hand side must equal the right hand side
4(5y-8-2)=185-15
20y-32-8=170
20y=170+32+8
20y=210
Therefore y=10,5
When you substitute the 10,5 and solve it on the left and side it's equal to 170 which is the answer on the right hand side
If y = x+2 and x = -3 then we can say that y = -3+2 after replacing the 'x' with -3
From here, we just add -3 and 2 to get -1 which is why y = -3+2 turns into y = -1
So together x = -3 and y = -1
They pair up to form (x,y) = (-3,-1)