In the diagram, what is the measure of angle 1?

C

Step-by-step explanation:

The adjacent angle to the left of 9x is 180 - 9x ( straight angle )

180 - 9x and 3x are corresponding angles and are congruent , then

3x = 180 - 9x ( add 9x to both sides )

12x = 180 ( divide both sides by 12 )

x = 15

Then

∠ 1 and 180 - 9x are vertically opposite angles and are congruent, so

∠ 1 = 180 - 9(15) = 180 - 135 = 45° → C

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".