Answer:
Step 3
Step-by-step explanation:
The solution is given in the image attached. The steps are:
Step 1:

Step 2: simplifying the coefficients of x:

Step 3: Adding 1/4 to both sides

Step 4: Multiplying both sides by 5/7

The addition property of equality states that if a number is added to both sides of an equation, the equation is still valid (i.e the equation is still the same). From the steps above, The addition property of equality was applied in step 3
They're not congruent.
If you count the numbers between AC and BE, they're different.
AC - goes from -7 to 0, which is 7 spaces
BE - goes from -2 to 6, which is 8 spaces
The axis of symmetry of a parabola in the form

is a vertical line

where k is the x coordinate of the vertex of the parabola.
The x coordinate of the vertex of the parabola is given by

which in your case is

So, the axis of symmetry is the line x=12.