3. Solve. Check Your Solutions
z - 12 = 30

z = 42

Step-by-step explanation:

z - 12 = 30

Add 12 to each side

z - 12+12 = 30+12

z = 42

Check

42 - 12 = 30

30 = 30

Step-by-step explanation:

If we want to solve this algebraic equation, we need to isolate z on one side.

Add 12 to both sides:

To check our work, let's substitute 42 in as .

42 minus 12 is indeed 30.

Hope this helped!

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.