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°
