Can someone help me solve this?

2. A park planner has sketched a rectangular park in the first quadrant of a coordinate grid. Two sides of the park lie on the x- and y-axes. A trapezoidal flower bed will be bounded by the line y = x + 7, the x-axis, and the vertical lines x = 1 and x = a, where a > 1. The area A of the trapezoid is modeled by 15 A = ja + 7a -7. Assume that lengths along the axes are measured in meters. For what value of a will the trapezoid have an area of 23 square meters? Use the Quadratic Formula to find the