Answer:
B. x=8
Explanation:
The 2 angles are consecutive interior angles, and therefore they are supplementary. This means that they add to 180 degrees.
(12x+8)+(8x+12)=180
Combine like terms. Add all the terms with a variable, then the terms without a variable.
(12x+8x)+(8+12)=180
20x+20=180
Now, solve for x by isolating x. Perform the inverse operation to both sides.
20 is being added to 20x. The inverse of addition is subtraction. Subtract 20 from both sides.
20x+20=180-20
20x=180-20
20x=160
x is being multiplied by 20. The inverse of multiplication is division. Divide both sides by 20.
20x/20=160/20
x=160/20
x=8
x is equal to 8, and B is the correct answer.