To do this, we can add $4x^2$ to both sides of the equation to eliminate the $-4x^2$ term on the right side:
$$
(-3x^2 + 4x^2) + 4x - 1 = -4x^2 + 4x^2 - 4x + 12
$$
$$
x^2 + 4x - 1 = -4x + 12
$$
Now, we can add $4x$ to both sides of the equation to eliminate the
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