Answer:
1) x = 9
2) y = 16
3) y = -1
Step-by-step explanation:
Do PEMDAS in reverse.
For every equation, your goal is to seperate the variable (x,y, or whatever letter) by itself.
1) 2x-7 = 11
Add 7 to both sides.
2x = 18
Divide both sides by 2.
x = 9
2) 
Divide both sides by 3/4 (which turns into multiplying by 4/3).
<u>Left side</u>

<u>Right side</u>
<u />
<u />
<u />
3) 9(y+3) = 18
Remember do PEMDAS in reverse.
Divide both sides by 9.
y+3 = 2
Subtract both sides by 3.
y = -1