PLEASE HELP ILL MARK BRINLIEST

Step-by-step explanation:

4+2S=12+S

in the left side there is one triangle so its value is 4 and two square so its value is 2S because you don't know the value of the square.

In the right side, there is 3 Triangles and one square so its value is 12 (3*4)+S

So,           S=8

how?

12+4=16

S=16/2=8

twenty-six miles over two gallons because the proportion for the original 13 miles to one gallon would be written 13/1 and, doing the same thing to the top and bottom, i multiplied by 2 and got 26/2