(7x -7) + (6x +6) = 90
take away the parenthesis: 7x - 7 + 6x + 6 = 90
combine like terms: 13x - 1 = 90
add 1 to both sides: 13x = 91
divide both sides by 13: x = 7.
Now: substitute x = 7 into the angles: the first angle is 42 degrees, the second angle is 48 degrees
