Answer:
1. 2
2. 3
3. 6
4. 3
5. 6
6. 3
7. -6
8. -3
9. 3
10. -5
11. 12
12. -18
13. -1
I'm sorry if any of these are wrong I didn't get to check them over.
Explanation:
I will be substituting "a number" with the variable x.
1. Four more than twice a number is 8.
2x+4 = 8
2x = 4
x = 2
2. Three more than four times a number is 15.
4x+3 = 15
4x = 12
x = 3
3. Five less than twice a number is 7.
2x-5 = 7
2x = 12
x = 6
4. One less than four times a number is 11.
4x-1 = 11
4x = 12
x = 3
5. Seven more than the quotient of a number and 2 is 10.
(x/2)+7 = 10
(x/2) = 3
x = 6
6. Six less than six times a number is 12.
6x-6 = 12
6x = 18
x = 3
7. Five less than the quotient of a number and 3 is -7.
(x/3)-5 = -7
x/3 = -2
x = -6
8. Seven more than twice a number is 1.
2x+7 = 1
2x = -6
x = -3
9. The difference between 5 times a number and 3 is 12.
5x-3 = 12
5x = 15
x = 3
10. Nine more than 3 times a number is -6.
3x+9 = -6
3x = -15
x = -5
11. Nine more than the quotient of a number and 4 is 12.
(x/4)+9 = 12
x/4 = 3
x = 12
12. Four less than the quotient of a number and 3 is -10.
(x/3)-4 = -10
x/3 = -6
x = -18
13. Nine less than six times a number is -15.
6x-9 = -15
6x = -6
x = -1