Final answer:
The equation 7x + 8x = 12 + (-12) simplifies to 15x = 0, and by dividing both sides by 15, we find that x = 0. Substituting back into the original equation confirms that the solution is reasonable and correct.
Step-by-step explanation:
To solve for the variable, we start by combining like terms on the left side of the equation:
7x + 8x = 12 + (-12)
15x = 0
As we see, the terms on the right side of the equation cancel each other out, so we're left with simply:
15x = 0
Next, to isolate x, we divide both sides of the equation by 15:
x = 0 / 15
x = 0
This means that the variable x is equal to 0. There is no need for further evaluation as the simplified equation directly gives us the answer. To ensure our solution is reasonable, we substitute x back into the original equation:
7(0) + 8(0) = 12 + (-12)
0 = 0
This confirms that our solution is correct since both sides of the equation are equal when x is 0.