Answer:
Explanation:
x and 3x are on a straight line together. Therefore, they are supplementary and must add to 180 degrees.
Add x and 3x, and set that equal to 180.
Combine like terms on the right side of the equation. Both x and 3x have a variable, so they can be added together.
Since we want to find x, we have to isolate x. x is being multiplied by 4. The inverse of multiplication is division. Divide both sides of the equation by 4.
x is equal to 45, so the correct answer is B. 45