these two angles are supplementary to each other. this is because alternate interior angles are congruent, and 2x+42 degrees is supplementary to the alternate interior angle of x-24 degrees. so, we can add these two numbers up and set it equal to 180.
2x+42+x-24=180
3x+18=180
3x=162
x=54
if this question is asking for x, 54 is the answer. if it is asking for the angle measures, plug in 54 for x for each angle and solve.
is red, than the remaining 
would be blue. 
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