The width of the rectangle is 3 cm less than its length, find the width of the rectangle if its area is 130 cm2.

We take the length of the rectangle as x, then we take the width, since it is 3 cm less than the length, then the width will be x – 3.
We are given that the area of the rectangle is 130 square cm.
The area of a rectangle is equal to the product of two adjacent sides.
x * (x – 3) = 130;
x ^ 2 – 3x = 130;

x ^ 2 – 3x – 130 = 0;

D = b ^ 2 – 4ac = 9 + 4 * 1 * 130 = 9 + 520 = 529.

√D = 23.

x1 = (-b + √D) / 2a = 3 + 23/2 = 26/2 = 13.

x2 = (-b – √D) / 2a = 3 – 23/2 = -20/2 = -10 – the root does not fit, since the negative side cannot be.

13 cm is the length of the rectangle.

13 – 3 = 10 cm – the width of the rectangle.