Question

The length of a rectangle is 4 centimeters less than its width. What are the dimensions of the rectangle if its area is 252 square​ centimeters?
Length=
Width=

Answer 1

L=w-4
a=l*w
a=w*(w-4)
252=w*(w-4)
Both numbers have to be multiples of 2 because 252 is even.
Both numbers have to be around 16 because √252 ≈15.9
You have to kind of mess around with it, 2 numbers 4 apart, around 16.
You'll get 18 and 14.

width=18
length=14

Hope this helps :)

Answer 2

A=LW
L=W-4
A=252

sub W-4 for L

A=(W-4)(W)
252=(W-4)(W)
252=W²-4W
minus 252 both sides
0=W²-4W-252
what 2 numbers multiply to get -252 and add to get -4
-18 and 14
0=(W-18)(W+14)
set to zero

W-18=0
W=18

W+14=0
W=-14
false, we can't have negative width


Width=18
L=W-4
L=18-4
L=14


length=14cm
width=18cm