(2x² - 5) - (3x² + 4).
Pretend that there is a -1 in front of :(3x² + 4).
(2x^2-5)-1(3x^2+4)
2x^2-5-3x^-4
2x^2-3x^2-5-4
=-x^2-9
Answer: -x^2-9
