Slope of one dotted lines:
slope of the reflection line:

Slope of dotted lines: 1

Slope of reflection line: -1

Step-by-step explanation:

For the dotted lines, the rise up by one unit and run for one unit, thus their slopes are 1.

For the reflection line, it does the same thing as the dotted line, but instead of rising one unit, it goes down for one unit and runs for one unit, making its slope -1.

histogram or dot plot?

step-by-step explanation:

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".