Answer:
x=8
Explanation:
We know that 40 + (6x+2) +90 = 180 since the three angles form a straight line
40 + (6x+2) +90 = 180
Combine like terms
132 + 6x = 180
Subtract 132 from each side
132-132 +6x= 180-132
6x = 48
Divide each side by 6
6x/6 = 48/6
x = 8