Question

the measure of one angle is 15 less than half the measurement of its supplement.

Answer 1

It is given in the question that

The measure of one angle is 15 less than half the measurement of its supplement.

Let the measurement of supplement angle is x degree.

So the measurement of the other angle is

$\frac{x}{2} -15$

And the sum of the measurement of supplementary angles is 180.

$x+ \frac{x}{2} -15 =180 \\ \frac{3x}{2} = 195$

Multiplying both sides by 2

$3x = 390 \\ x = 130$

So one angle is of measurement 130 degree and the other angle is of  measurement 50 degree.