Answer:
Step-by-step explanation:
So the sum of 128 and x+10 is on a straight line which is 180º right?, so:
x + 10 + 128 = 180
x = 180 - 128 - 10
x = 42º
42
x +10 +128 = 180 {Linear pair}
x + 138 = 180
x = 180 - 138
x = 42
