Answer: C x = -2
Step-by-step explanation:
[tex]3x^{2} - 30x - 72 = 0[/tex]
[Add 72 on both sides]
[tex]3x^{2} - 30x = 72[/tex]
[Factorise Left Hand Side of equation to get 3 on one side of a bracket]
[tex]3(x^{2} -10x) = 72[/tex]
[Divide each side by 3 to just get the brackets and the x's on one side]
[tex]x^{2} -10x = 24[/tex]
[Minus 24 on both side as the equation must = 0]
[tex]x^{2} -10x-24=0[/tex]
[Solve the square on the left hand side]
[tex](x-12)(x+2)=0[/tex]
[Solve for x on left hand side - two possible answers]
[tex]x-12=0 \\ x=12[/tex]
[tex]x+2=0\\x=-2[/tex]
[The answer '12' is not in the option for the question so '-2' is the answer]
