Explanation:
11. Angle A and B are supplementary (add to 180)
And measure of Angle A is 2x+30 and measure of angle B is 6x-12. All you have to do is make an algebraic expression.
180= (2x+30) + (6x-12)
Then just combine like terms and you get
8x+18=180.. Subtract 18 and you get
8x=162 then divide by 8 and you get
X=20.25
Then plug in the number and you get
180=(2*20.25+30)+(6×20.25-12)
Which is is transferred to
180=(70.5) +(109.5)
Which is 180=180.
The measure of angleA is 70.5°
You can try the other's if you want if not then
9. Value of x is 33.5
10. Measure of angleB 90°
12. Measure of angleA 24°
(im not writing that much again.)