Simple....
you have:
3x-9=7x+12
To even solve this....isolate the variable your are trying to solve for....
3x-9=7x+12
-3x -3x
-9=4x+12
-9=4x+12
-12 -12
-21=4x
Simplify.....


Thus, your answer.
A. x+5 (divided by 4)
b. 2x+20 (multiplied by 2)
Answer:
6.9 to the nearest tenth.
Step-by-step explanation:
Use the external tangent - chord theorem:
AP^2 = CP * BP
AP^2 = 12 * 4 = 48
AP = √48
= 6.928