Elementary Algebra

To find the $y$-intercept of an equation of a graph, we plug in $0$ for $x$ and solve for $y$. We plug in $0$ for $x$ and apply the principles of equivalency to solve the equation for $y$: $$3x+4y=-12$$ $$3(0)+4y=-12$$ $$4y=-12$$ $$\frac{4y}{4}=\frac{-12}{4}$$ $$y=-3.$$ Since $y\ne-4$, the statement is false.