What is one possible value of x in this equation x^2-3x-18=0

Either - 3 or 6.

You can write this equation as a function, then factor it. You can use the zero-factor rule (I think that's what it's called) to find the x-intercepts of the function, where the equation is equal to zero.

y=x^2-3x-18

Factor by grouping;

y=x^2+3x-6x-18

y=x (x+3) - 6 (x+3)

y = (x+3) (x-6)

When y=0, (x+3) = 0 or (x-6) = 0

x+3=0 when x=-3, and x-6=0 when x=6

Your possible values of x are - 3 and 6.

x=6,-3

Step-by-step explanation:

x²-3x-18=0

Find two numbers that multiply to get - 18, and add to get - 3!

(These two numbers are - 6 and 3)

Now write them in an equation:

(x-6) (x+3) = 0

Set both equations equal to 0:

A) x-6=0

B) x-3=0

2A) x=6

2B) x=-3