Someone please help me with these three problems, I really need to get my grade up

81=16x²+24x+9
72=8(2x²+3x)
9=2x²+3x
0=2x²+3x-9
0=(2x-3)(x+3)
X=3/2 or -3
18=36x²+12x+1
0=36x²+12x-17
x=(-12±√(144-4(36)(-17))/2(36)
X=0.54 or 0.874
28=25x²+40x+16
0=25x²+40x-12
X=(-40±√(40²-4(25)(-12))/2(25)
X=-1.858 or 0.258