Please answer this.

Step-by-step explanation:

10)a) Let the number = x

4x + 8 = 16

Subtract 8 form both sides

4x + 8 - 8 = 16 - 8

4x = 8

Divide both sides by 4

4x/4 = 8/4

x = 2

The number is 2

b) Let the number = x

4x - 8 = 6

Add 8 to both sides

4x - 8 + 8 = 6 + 8

4x = 14

Divide both sides by 4

4x/4 = 14/4

x = 3.5

The number is 3.5

11) a) Increase in cost = 105 - 100 = $ 5

b) Percentage increase =

                                       = 5%

12)  Number of girls = 35

Number of girls wearing glasses  = 15

Number of boys = 40

Number of boys wearing glasses  = 10

a) Percentage of boys wearing glasses =

                                                                 = 25%

b) Percentage of girls wearing glasses =

                                                                 = 42.86%

c) Total children = 35 +40 = 75

Total children wearing glasses = 15 + 10 = 25

Percentage of children wearing glasses =

                                                                        = 33.33%

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".

175

step-by-step explanation:

2 inches x 10 miles = 200 miles - 3 inches = 175