1. Let's clarify the expression and the operation you are referring to. 2. Suppose you have an expression like $-3x^2$ and you mention canceling an $h$; this suggests you might be working with a difference quotient or a limit involving $h$. 3. The term $-3x^2$ means negative three times $x$ squared, which is $-3 \times (x^2)$. 4. If you had an expression like $-3(x+h)^2$ and you subtract $-3x^2$, you would expand and simplify: $$-3(x+h)^2 + 3x^2 = -3(x^2 + 2xh + h^2) + 3x^2 = -3x^2 - 6xh - 3h^2 + 3x^2$$ 5. Notice that $-3x^2$ and $+3x^2$ cancel each other out, leaving: $$-6xh - 3h^2$$ 6. The remaining terms still have $h$ in them, so you cannot cancel $-3x$ alone; the negative sign and the square on $x$ are part of the original term. 7. Therefore, the negative sign applies to the entire $3x^2$ term, and canceling $h$ does not change that. In summary, $-3x^2$ is negative three times $x$ squared, and canceling $h$ in a difference quotient removes terms involving $h$, but does not change the negative sign or the squared term on $x$.