For ABC:
The interior angle of C is 180 - 142 = 38
The three interior angles add up to 180°
(2x - 15) + (x - 5) + 38 = 180
3x - 20 + 38 = 180
3x + 18 = 180
3x = 162
x = 54
The measure of angle ABC = x - 5 = 54 - 5 = 49
For JKL:
The interior angle of L is 180 - 100 = 80°
The 3 interior angles add up to 180°
(2x + 27) + (2x - 11) + 80 = 180
4x + 16 + 80 = 180
4x + 96 = 180
4x = 84
x = 21
The measure of angle JKL is 2x - 11 = 2(21) - 11 = 42 - 11 = 31°
