James C. answered 01/30/21
BS in Mathematics with 20+ years of teaching experience
The first angle should be 3x - 3. You have the expression for the second angle written correctly.
The base angles are congruent in isosceles trapezoids so
3x - 3 =24 + 2x
I would subtract 2x from each side first
x - 3 = 24
Then add 3 to each side
x = 27. The work you showed doesn't really make sense mathematically because your equation doesn't equal anything.
We have found x, but they want the measure of all the angles.
So for the acute angles, we substitute 27 in for x in either expression
24 + 2(27) = 24 + 54 = 78.
The acute angles and obtuse angles inside the trapezoid are supplementary so they add up to 180.
180 - 78 = 102.
The acute angles measure 78 degrees and the obtuse angles measure 102 degrees.