Answer:
1. x=9
2 x=9
3 x=10
4 x=7
Step-by-step explanation:
1. 15+5x + 14x-6 = 180 supplementary angles
combine like terms
9 + 19x = 180
subtract 9 from each side
19 x = 171
divide by 19
19x/19 = 171 /19
x = 9
2. 13x-7 = 11x+11 corresponding angles are equal
subtract 11x from each side
2x -7 = 11
add 7 to each side
2x = 18
divide by 2
x =9
3. x+ 100 = 90 alternate interior angles are equal
subtract 100 from each side
x = -10
4. 17x+1 = 120 alternate exterior angles are equal
subtract 1 from each side
17x = 119
divide by 17 on each side
x = 119/17
x=7
