Answer:
x=12
Step-by-step explanation:
To make these 2 lines perpendicular to each other, one of their angles must be equal to 90 degrees.
Therefore, we can set up an equation with one of the angles:
7x+6=90
7x=84
x=12
The information of the other angle is useless in this case, but we can use it to check by plugging in 12 for x, and seeing if it equals to 90:
8*12-6=96-6=90
Therefore, x=12.