you have to distribute it or use FOIL (if u know that method). This is basically factoring.
for instance:
(2x-9)×(x+4)
first: 2x × x = 2x^2
second: 2x × 4 = 8x
third: -9 × x = -9x
forth: -9 × 4 = -36
now combine like terms.
2x^2 + 8x -9x - 36
(8x and -9x are like terms)
(add the two together, which is -1x or -x)
2x^2 -x -36 is ur answer
now do this same method for the rest
