What is the supplement of a 90-x angle."

90 + x

Step-by-step explanation:

supplementary angles are angles that add up to 180.

90 + 90 = 180

-x + x = 0

90-x + 90 + x = 180.

so, your answer would be 90 + x

Check! lets say X = 6

90-6  + 90 + 6 = 180.

Good luck with your schoolwork/homework!

apologies in advance for incorrect answers or bad explanations.

the first option is the answer.