How can you express (15+30) as a multiple of a sum of whole numbers with no common factor ?​

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

A. 127 cm^2 b. 144.5 cm^2 c. 172 cm^2 d. 50 cm^2

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36