Me with this math problem i will give brainliest for the right answer.

show your work**

The answer is 9x-4.

Step-by-step explanation:

First calculate the area of the backyard. This is 13x-1. Then multiply the area of the patio so multiply x +3 by x+ 3. The answer to this is 4x+3. Next subtract the area of the patio from the area of the backyard. The answer is 9x-4.

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".