Which expression represents "5 less than the product of 7 and x

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.

Can someone answer this question? : )

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.