Answer:
<h2>
width = 3 feet</h2>
Step-by-step explanation:
Let h be the height of the door
and w be its width
The statement “The height of the door is I foot more than twice its width”
can be translated mathematically like this : h = 2w + 1
Let’s solve the equation for w:
h = 2w + 1
⇔ 2w = h - 1
now , if the door is 7 feet high then it’s width is equal to :
Vocab:
Parallel = same slope
Perpendicular = opposite sign and reciprocal slope
-5/2 opposite and reciprocal = 2/5
Solution: they are perpendicular
You can write two equations using the given information:
.. L = W +8
.. L * W = 609
Using substitution, you get a quadratic.
.. (W +8) * W = 609
.. W^2 +8W -609 = 0
Not surprisingly, you're looking for factors of 609 that differ by 8.
.. 609 = 1*609 = 3*203 = 7*87 = 21*29
The last two are the factors of interest.
.. (W +29)(W -21) = 0
The width of the rectangle is 21 feet, the length is 29 feet.
_____
Sometimes it is easier to work with the average dimension. Here, let that be x. Then you have
.. (x +4)(x -4) = 609
.. x^2 -16 = 609
.. x^2 = 625 = 25^2 . . . . . . . one of your memorized math facts
So, the dimensions are
.. 25 +4 = 29 by 25 -4 = 21, that is, 29 ft by 21 ft.
F=3; f=7 hope this helps !
This is it, it will open down :)
