Step 1: rewrite the equation
(5x²-5x+4) + (8x³-9x)
Step 2: open the brackets
5x²- 5x + 4 + 8x³- 9x
Step 3: organize in the value of the exponent
8x³+ 5x²- 5x - 9x + 4
Step 4: simplify :)
8x³+ 5x²- 14x + 4
Step 5: That's the answer
= 8x³+ 5x²- 14x + 4