Answer:
x = 8
y = 21
Step-by-step explanation:
The angle (7x + 12)° and the angle (12x-28)° are alternate interior angles and so has got the same measurement
7x + 12 = 12x - 28
12 + 28 = 12x - 7x
40 = 5x divide both sides by 5
8 = x
The sum of angle (12x - 28)° and (9y - 77)° must be equal because they make a straight line with the measure of 180°
12x - 28 + 9y - 77 = 180 we already found the value of x as 8 so let's rewrite the equation
12 × 8 - 28 + 9y - 77 = 180
96 - 28 - 77 = 180 add like terms
9y - 9 = 180
9y = 189 divide both sides by 9
y = 21
