A line about which a figure is symmetric--is the

Axis of symmetry

Step-by-step explanation:

An axis of symmetry  divides the parabola in 2 parts. The axis of symmetry goes through the vertex and the x coordinate of vertex is also the equation of the axis.

step-by-step explanation:

y=mx+b

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".