Question

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

Answer 1

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