Answer:
4x^2 + 21x - 18
Step-by-step explanation:
(9x^2+24x-8)-(5x^2+3x+10)
9x^2+24x-8-5x^2-3x-10
9x^2 - 5x^2 = 4x^2
24x - 3x = 21x
-8 - 10 = -18
Answer: 4x^2 + 21x - 18