Find the length and width of a rectangular section if its area is 800 m2 and the length is 20 m greater than the width.

Let the width of a rectangular section be x meters, then the length of this section is (x + 20) meters. By the condition of the problem, it is known that the area of the site is (the area of the rectangle is equal to the product of its length and width, S = ab) x (x + 20) m ^ 2 or 800 m ^ 2. Let’s make an equation and solve it.

x (x + 20) = 800;

x ^ 2 + 20x = 800;

x ^ 2 + 20x – 800 = 0;

D = b ^ 2 – 4ac;

D = 20 ^ 2 – 4 * 1 * (-800) = 400 + 3200 = 3600; √D = √3600 = 60;

x1 = (-20 + 60) / (2 * 1) = 40/2 = 20 (m) – width;

x2 = (-20 – 60) / 2 = -80/2 = -40 – the length may not be negative.

x + 20 = 20 + 20 = 40 (m) – length.

Answer. 20 m; 40 m.