Answer:
7. x=3, 8. x=7, 9. x=15.
Step-by-step explanation:
7. If lines m and n are congruent, then angles DCF and CFE are congruent. 15x+3=18x-6. Solve for x. --> 15x+9=18x-->3x=9-->x=3
8.If line m is parallel to line n, then the corresponding angles are congruent. So, 20x+1=22x-13 Solve for x. 20x+14=22x-->14=2x-->x=7.
9. The supplementary angle of 110 is 70. Note that all of the inner angles of a triangle are equal to 180. Form an equation using the the values: (4x+8)+(2x+12)+70=180. Simplify; 6x+90=180. Solve for x: 6x+90=180-->6x=90-->x=15.
Hope this helps!
