Question

The length of a rectangle is 3m more than twice its width, and the area of the rectangle is 77m^2 . Find the dimensions of the rectangle.

Answer 1

that would be the formula to find the length and width?

Answer 2

Well, it gave the area, so we have to use the formula for area of a rectangle to find it

A = xy

Answer 3

2x + 3 = length
x = width

A = x(2x+3)

77 = 2x^2 + 3x

2x^2+3x - 77 = 0

Now it's correct :D

Answer 4

so to get the length and width have to solve the equation right?

Answer 5

Yes

2x^2+3x - 77 = 0
2x^2 + 14x - 11x - 77 = 0
2x(x+7)-11(x+7) = 0
(x+7)(2x-11) = 0

x = -7
x = 11/2 or 5.5
2x + 3 = 14

Answer 6

5.5 x 14 = 77

Answer 7

By the way x = -7 is not a solution

Answer 8

so then if the width is -7 ..?

Answer 9

and the length is 14

Answer 10

No. If you notice, there are two solutions for x. I already told you that x = -7 is not a solution.

Answer 11

then the length is 14 "?