Answer:
31x
Explanation:
Were just looking at the top triangle because it has the points A,B, and D. now we solve for x (aka answer the equation in the parentheses). We need to get rid of the 22 so we only have x. We do that by adding it to itself so it equals 0. What we do to one side we do to the other. Now adding 22 to 9 we get 31 (put the x back).
9x - 22
+22 +22
9x - 22 = 31x