Solve.
2(z - 10) = -4

z=8

Step-by-step explanation:

Step 1: Simplify both sides of the equation.

2(z−10)=−4

(2)(z)+(2)(−10)=−4(Distribute)

2z+−20=−4

2z−20=−4

Step 2: Add 20 to both sides.

2z−20+20=−4+20

2z=16

Step 3: Divide both sides by 2.

2z2=162

z=8

No, he made a mistake solving for the volume of both figures.

Step-by-step explanation:

You can just look at the formula and see it

Volume of a square pyramid : V=1/3bh , he forgot to use the 1/3. Volume of a cylinder: πr^2h , he forgot the π