First we notice that angles 1 and (20x+5) are supplementary, and we also notice that angle 1 and (24x-1) are alternate exterior angles. If lines a and b are parallel then the exterior angles mentioned before should be equal. If this happens we have that:
Once we know the value of x, then we can plug it in the expression for angle 1:
Therefore the value of 1 that proves that the lines are parrallel is 95°.