Solve 70+0.9*0.9y+370+120+40-0.31y=y

$$70+0.9 \cdot 0.9y+370+120+40-0.31y = y$$

Solve for y

$$y=1200$$

Steps for Solving Linear Equation

Multiply 0.9 and 0.9 to get 0.81.

$$70+0.81y+370+120+40-0.31y=y$$

Add 70 and 370 to get 440.

$$440+0.81y+120+40-0.31y=y$$

Add 440 and 120 to get 560.

$$560+0.81y+40-0.31y=y$$

Add 560 and 40 to get 600.

$$600+0.81y-0.31y=y$$

Combine 0.81y and -0.31y to get 0.5y.

$$600+0.5y=y$$

Subtract y from both sides.

$$600+0.5y-y=0$$

Combine 0.5y and -y to get -0.5y.

$$600-0.5y=0$$

Subtract 600 from both sides. Anything subtracted from zero gives its negation.

$$-0.5y=-600$$

Divide both sides by -0.5.

$$y=\frac{-600}{-0.5}$$

Expand \frac{-600}{-0.5} by multiplying both numerator and the denominator by 10.

$$y=\frac{-6000}{-5}$$

Divide -6000 by -5 to get 1200.

$$y=1200$$