Two angles with measures (5x+7) and (15x-7) are supplementary. What is the value of X?

supplementary angles add up to 180

so solve 5x+7 + 15x-7 = 180 for x
then sub that value of x into both of the angles.

To find the value of x, let's set up the equation by using the fact that two angles are supplementary when their sum is 180 degrees.

The sum of the two angles, (5x + 7) and (15x - 7), is equal to 180 degrees:

(5x + 7) + (15x - 7) = 180

Now, simplify the equation by combining like terms:

20x = 180

Next, isolate x by dividing both sides of the equation by 20:

x = 180 / 20

Simplifying further:

x = 9

Therefore, the value of x is 9.