The width of the rectangle is 3cm less than the length. Find the width of the rectangle if its area is 18cm ^ 2.

It is known from the condition that the width of the rectangle is 3 cm less than the length. And we also know the area of the rectangle is 18 cm2.

Let’s denote by x cm the length of the rectangle, then the width can be written as (x + 3) cm.

Let’s remember the formula for finding the area and use it to form an equation:

S = a * b;

x (x + 3) = 18;

x ^ 2 + 3x – 18 = 0;

D = b ^ 2 – 4ac = 9 + 72 = 81;

x1 = (-3 + 9) / 2 = 6/2 = 3;

x2 = (-3 – 9) / 2 = -12/2 = -6 the second root does not fit.

3 cm rectangle length, 3 + 3 = 6 cm rectangle width.