-3|x|=9, what is x? I wrote that x = -3, but I guess that's wrong?

It is correct

Step-by-step explanation:

It is correct since the product of 2 negatives is always a positive:

Also since it is the same number being multiplied the answer is a square number:

that is why the square root of anything is known as ±.

Since there are 2 solutions, this also explains why there are 2 solutions in a quadratic equation.

the axial of symmetry

step-by-step explanation:

the slope of the line is 60

one point on the line is (40,10)

step-by-step explanation:

in the equation outside the parenthesis the equation always tells you the slope. in this case it is 60.

in the parenthesis is also says 40 which is x because it is near the x and 10 is y because it is near y.