Question 949946
Complementary angles are those that add up to 90 degrees.

Let one angle be 3(x-10), just like the problem says. The other angle is just x.

x + 3(x - 10) = 90 Simplify
x + 3x - 30 = 90 Add 30, both sides. Also add x's on the left
4x = 120 Divide both sides by 4
x = 30, and 3(30-10)= 60