#### Answer

The solution is -80

#### Work Step by Step

57y +140=54y-100 Subtract 54y to both sides
57y +140 -54y=54y-100-54y Simplify
3y +140=-100 Subtract 140 from both sides
3y +140 -140=-100 -140 Simplify
3y=-240 Divide both sides by 3
$\frac{3y}{3}$=$\frac{-240}{3}$
y=-80
The solution is -80
Check
57y +140=54y-100
57(-80)+140=54(-80)-100 Multiply
-4560 +140 =-4320 -100
-4420=-4420