First set up the equation:

Then substitute in known values:

and solve for C

Simplifying
8x + -6 = 7x + 10
Reorder the terms:
-6 + 8x = 7x + 10
Reorder the terms:
-6 + 8x = 10 + 7x
Solving
-6 + 8x = 10 + 7x
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '-7x' to each side of the equation.
-6 + 8x + -7x = 10 + 7x + -7x
Combine like terms: 8x + -7x = 1x
-6 + 1x = 10 + 7x + -7x
Combine like terms: 7x + -7x = 0
-6 + 1x = 10 + 0
-6 + 1x = 10
Add '6' to each side of the equation.
-6 + 6 + 1x = 10 + 6
Combine like terms: -6 + 6 = 0
0 + 1x = 10 + 6
1x = 10 + 6
Combine like terms: 10 + 6 = 16
1x = 16
Divide each side by '1'.
x = 16
Simplifying
x = 16
HOPE I HELPED!!! :)
B is the correct answer 12
1.
(10m - 14) + 9 = 12 1. Given
2. 5m - 7 + 9 = 12 2. Distributive Property
3. 5m + 2 = 12 3. Simplify (added like terms)
4. 5m = 10 4. Subtraction Property of Equality
5. m = 2 5. Division Property of Equality