2+1 is what I’m so confused please help

Create and solve a linear equation that represents the model, where squares and triangles are shown evenly balanced on a balance beam. assume the weight of a square is 1 unit and the weight of a triangle is unknown.

One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

Find the perimeter of the figure shown above. a. 18 yds c. 20 yds b. 10 yds d. 24 yds select the best answer from the choices provided