Solve for x 19-24. find the measure of the angle indicated in bold for 25-28.

N 19) 
angle (21x+6) is equal angle 90°> by alternate exterior angles
so
21x+6=90> 21x=84> x=4°

the answer  N 19) is 4 degrees

N 20)
angle 75 is equal angle 11x-2> by corresponding angles
so
11x-2=75> 11x=77> x=7°

the answer N 20) is x=7 degrees

N 21)
angle 60 is equal angle (8x-4)> by alternate interior angles
so
8x-4=60> 8x=64> x=64/8> x=8°

the answer N 21) is x=8 degrees

N 22) 
angle (x+139) is equal to angle 132> by alternate interior angles
so
x+139=132> x=132-139> x=-7 °

the answer N 22) is x=-7 degrees

N 23) 
angle (-1+14x) is equal to angle (12x+17)>  by alternate exterior angles
so
-1+14x=12x+17> 14x-12x=17+1> 2x=18> x=9

the answer N 23) is x=9 degrees

N 24) 
angle (23x-5) is equal to angle (21x+5)> by corresponding angles
so
23x-5=21x+5> 23x-21x=5+5> 2x=10> x=5

the answer N 24) is x=5 degrees

N 25)
angle (x+96) and angle (x+96)> are supplementary angles
so
x+96+x+96=180>2x+192=180>  x=-6°
the angle indicated in bold is (-6+96)=90°

N 26) 
angle (20x+5) and angle (24x-1)> are supplementary angles
so
20x+5+24x-1=180> 44x=176> x=4°
the angle indicated in bold is (20*4+5)=85°

N 27)
angle (6x) is equal to angle (5x+10)> by corresponding angles
so
6x=5x+10> 6x-5x=10> x=10
the angle indicated in bold is (6*10)=60°

N 28)
angle (x+109) and angle (x+89) are supplementary angles
so
x+109+x+89=180> 2x=-18> x=-9
the angle indicated in bold is (x+89)> -9+89=80°