Which expression has the same sum as the one below -15+6

Apark is in the shape of a rectangle. the park authorities are planning to build a 2-meter-wide jogging path in the park (shown as the shaded region in the image). what is the area of the jogging path? plz

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'