Trevor and marissa together have 26 t-shirts to sell. if marissa has 6 fewer t-shirts than trevor, find how many t-shirts trevor has.

Let Trevor = t, and Marissa = m

m + t = 26

m = t - 6

Plug in t - 6 for m

(t - 6) + t = 26

Simplify. Combine like terms.

2t - 6 = 26

Isolate the t. Note the equal sign. What you do to one side, you do to the other. Do the opposite of PEMDAS.

2t - 6 (+6) = 26 (+6)

2t = 32

2t/2 = 32/2

t = 16

Trevor sells 16 shirts.

Subtract 16 from 26

26 - 16 = 10

Marissa sells 10 shirts.

hope this helps