Question

A rectangle with area 36 square inches has a length that is 3 less than 3 times the width. Find the length and the width of the rectangle.

Answer 1

Answer:

length = 9 in ; width = 4 in

Step-by-step explanation:

1) formula of the area of a rectangle

A = base x width

2) write an equation with the given informations:

w x (3w-3) = 36

3) solve the equation

-  multiply W by 3w and -3

3w^2 -3w = 36

- divide the two members by 3

w^2 - w = 12

- add up -12 at the two members

w^2-w -12 = 12 -12

w^2 - w - 12 = 0

- find two numbers whose sum is -1 and whose product is -12 and factorise the equation

(w-4)(w+3) = 0

- find the two solutions

w-4 = 0

w = 4

w+3 = 0

w = -3

4)remember that a length can’t be negative.

w = 4 is the only solution

5) find the length

4x3 - 3 = 9