Answer:

Step-by-step explanation:
x = measure of the first angle
y = measure of the second angle
z = measure of the third angle
The sum of the measures of the second and third (y+z) is five times the measure of the first angle (=5x)

The third angle is 14 more than the second

And remember that the sum of these three angles must be equal to 180.

Let's take these equations

If you take a look at the first equation, we have y+z = 5x and we have y+z in the third equation as well, we can replace that....

Distribute the + sign

Combine like terms;

Divide by 6.

We have now defined that the measure of the first angle is 30º.
Let's take another equation... for example 
I'm going to take this one because if I replace x and z in the third equation, all I'll have left will be y.

Distribute the + sign and Combine like terms;

Subtract 44 to isolate 2y.

Now divide by 2.

We already have the value of x and y. Once again, replacing this in the third equation will leave us with z to solve for.
