I need help with this question Please help ME!

Function: y = x - 6

input        output

1                 -5

2                 -4

3                 -3

4                 -1

the sum of all the angles in a triangle are equal to 180

so you can add   the 3 given angles together to equal 180:

5y + 2y + 2y = 180

or since all three angles have the same letter, combine the 3 angles to equal 180:

9y = 180