```Question 248262
2x^2=11
don't know if this is right thus far and where to go from here.
if this were right you would divide by 2
x^2=11/2
then get sqrt
x=sqrt(11/2)

Address book. The perimeter of the cover of an address book
is 14 inches, and the diagonal measures 5 inches. What are
the length and width of the cover?
It appears you are too anxious to do the problems that you aren't reading them.
what is 14?
14 is the perimeter.
What is the perimeter.
Someone who walks the perimeter of the ranch walks around the edge of the ranch.
so the perimeter is the walk around the rectangle or circle. since it is an address book It is a rectangle maybe a square.
In either case P=2L+2W
in the case of a square L=W
so we have now 2L+2W=14
2(L=W)=14
l+w=7

the diagonal measures 5 inches
What is the diagonal of rectangle?
It is the hypotenuse of the right triangle formed by the sides L and W

so we know that W=7-L
using the Pythagorean theorem a^2+b^2=c^2
but we have W^2+L^2=5^5
and W=7-L
substitute 7-L for W
and we get and that (7-L)^2+L^2=5^2
multiply it out using FOIL
(7-L)(7-L)
first
7*7=7^2=49
outside
7*-L
inside
7*-L
last
-L*-L=L^2
putting it altogether and rearranging to normal format
L^2+L^2-14L+49=25
2L^2-14L+24=0
divide by 2
L^2-7L+12=0

*[invoke quadratic "x", 1, -7, 12 ]

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