Help me. Ksjsjsjs:(

a rule to know: a median divides the side into equal parts.

we know:

PR = -2a + 34

SR = 2a + 26

- based on the rule, SR is half of PR. in other words, PR is two times greater than SR.

so,

2SR = PR (now simply pluggin the expressions we have)

2(2a + 26) = -2a + 34 (solve the equation like any other equation prob.)

4a + 52 = -2a + 34

6a + 52 = 34

6a = -18

a = -3

- inorder to check if this is correct, simply reverse what we did. so pluggin the value of a to see if its correct.

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".