A). They are supplementary angles meaning they add up to 180
So
B) (12x+8)+(3x+7)=180
12x+8+3x+7=180
15x+15=180
-15 -15
15x=165
15/15x=165/15
x=11
Angle 1 is
12x+8
12(11)+8
132+8
140
Therefore measure of angle 1 is 140°
Angle 2
3x+7
3(11)+7
33+7
40
Measure of angle 2 is 40°
