Find the solutions of 5x^2 -20x +20= 0

Jayne is studying urban planning and finds that her town is decreasing in population by 3% each year the population of her town is changing by a constant rate

We just started the introduction into circles and i have no idea how to do this.

Write the summation to estimate the area under the curve y = 1 + x2 from x = -1 to x = 2 using 3 rectangles and right endpoints