Solve 1200=(5)(8)(z1-20)

$$1200=(5)(8)(z1-20)$$

Solve for z_1

$$z_{1}=50$$

Steps for Solving Linear Equation

Multiply 5 and 8 to get 40.

$$1200=40\left(z_{1}-20\right)$$

Use the distributive property to multiply 40 by z_{1}-20.

$$1200=40z_{1}-800$$

Swap sides so that all variable terms are on the left hand side.

$$40z_{1}-800=1200$$

Add 800 to both sides.

$$40z_{1}=1200+800$$

Add 1200 and 800 to get 2000.

$$40z_{1}=2000$$

Divide both sides by 40.

$$z_{1}=\frac{2000}{40}$$

Divide 2000 by 40 to get 50.

$$z_{1}=50$$