Please help me! Pls!! ASAP

Which is an equation for the nth terms of the sequence 12,15,18,21

Which polynomial function has x intercepts -1, 0, and 2 and passes through the point (1, -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