Posted by Karina on Sunday, April 10, 2011 at 11:14pm.
The length of a rectangle is three less than three times the width. The area is 90ft^2. Find the width and the length of the retangle.
math - Jai, Sunday, April 10, 2011 at 11:37pm
first we represent the unknowns using variables,,
let x = width
let 3x-3 = length (according to the first statement)
now we set up the equation,, since we are given the area, recall that the area of a rectangle is
A = L*W
where L=length and W=width.
90 = (3x - 3)(x)
90 = 3x^3 - 3x
0 = 3x^2 - 3x - 90
we can factor out the 3 and just cancel it (since the other side of equation is zero):
0 = 3(x^2 - x - 30)
0 = x^2 - x - 30
since it's factorable,
0 = (x+5)(x-6)
x = -5 and x = 6
since measurements can never be negative, we only take the positive root:
x = 6 ft (width) ; and
3x-3 = 15 ft (length)
hope this helps~ :)
Answer This Question
More Related Questions
- basic geometric - 10. a rectangle has width the same as a side of a square whose...
- math - The length, l, of a rectangle is 2 feet less than three times the width, ...
- math - If x represents width of rectangle & length is 4 less than 3 times the ...
- geometric - The perimeter of a rectangular carpet is 70feet. The with is three -...
- Algebra - The length of a rectangle is 2 ft less than three times the width. The...
- math - Two less than three times the width of a rectangle is equal to the length...
- algebra 1 - The length of a rectangle is three less than four times its width. ...
- math - The area of a rectangle is 77 yd2 , and the length of the rectangle is 10...
- Algebra Homework, HELP! - 1) A rectangle has an area of 297 square inches and a...
- Algebra - If the trend continued, in how many years would the median home value ...