Answer: X = 8
Explanation:
You should already know that the angle is a 90 degree angle. So, you can write the equation: (7x+1) + (3x+9) = 90
Put all the numbers without variables to the right of the equation so it becomes:
7x + 3x = 90 - 9 - 1
10x = 80
10(8) = 80
80 = 80