Two complementary angles are 2x +12`, and x +21`, find x.
Solution:
As we know the in complementary angles the sum of two angles is equal to 90o.
So (2x + 12) +( x + 21) = 90
2x + 12 + x + 21 = 90
3x + 33 = 90
3x = 90 - 33 = 57
x = 57/3 = 19.
Ans: 19.