Answer:
(5x³+4x²) - (6x²-2x-9) equals 5x³ -2x² +2x + 9.
Explanation:
(5x³+4x²) - (6x²-2x-9)
Since there is a minus sign in front of the second expression, then all of the signs within the paraentheses are going to change to their opposites. So, for example, 6x² becomes -6x².
5x³ + (4x²-6x²) + 2x + 9
5x³ -2x² +2x + 9
So, (5x³+4x²) - (6x²-2x-9) equals 5x³ -2x² +2x + 9.