The measure of an angle is 20 less than 3 times its supplement. Find the measure of the angle.?

Question

Can someone explain exactly how to do this so I can get a complete understanding and do it myself next time?

Answer 1

Supplementary angles add up to 180. So the supplement of an angle measuring x is an angle that measures (180-x).

The statement can be written as this equation:
3(180 - x) - 20 = x

Solve for x:

3(180 - x) - 20 = x
540 - 3x - 20 = x
520 = 4x
130 = x

Now Let's check:

If x is 130, then the supplement of x is 180-130 = 50.
Three times the supplement of x is 3*50 = 150.
And 20 less than that is 150-20 = 130.

Answer 2

Call the angle x. Its supplement y is the angle where x+y=180.

x=3y-20

is what the question says. We also know y=180-x. Thus:

x=3(180-x)-20

x=540 - 3x -20

4x=520

x= 130

This is true, check to find y=50 and 3y=150, 20 more than x.

Answer 3

x + y =180

x + 3x - 20 = 180

4x -20 = 180

add 20 to both sides

4x = 200

divide both sides by 4

x = 50

the other angle is 130

Answer 4

let the angle bex
x=3()180-x)-20
x=540-3x-20
4x=520
x=130 deg answer