Respuesta :
The expression is the following:
[tex](2x^3+9x-12)-(3x^3-9)[/tex]First, we need to evaluate the parenthesis. The first one doesn't have any factors multiplying, dividing or another opration that require it, so we can just remove it:
[tex]2x^3+9x-12-(3x^3-9)[/tex]Now, the second parenthesis have a "-" sign in front of it, so we need to distribute this sign to each term inside the parenthesis. We can think of it as multiplying each term by "-1":
[tex]\begin{gathered} 2x^3+9x-12-(3x^3-9) \\ 2x^3+9x-12-3x^3+9 \end{gathered}[/tex]No, we pair the like term. Like terms can be classifyied by the x part and its exponent. We have 3 types here, the ones without x, the ones with x to the first (simply x) and the one with x to the third (x³).
[tex]2x^3-3x^3+9x-12+9[/tex]And now we evaluate the like terms to get the simplifyed expression:
[tex]-x^3+9x-3[/tex]