We can solve this problem using discriminant.
x^2-4x-12's discriminant is
(-4)^2-4*-12=16+48 which is clearly larger than 0
This means that it crosses over the axes 2 times.
In case you don't know what discriminant is, its in equation ax^2+bx+c
the discriminant is b^2-4ac.
If its positive it has 2 crosses with x axis, if negative then 0 crosses, if 0 then 1 cross.
Hope this helped at least a little bit :D
Which page is this in the book
The limit is equivalent to the value of the derivative of

at

. (See definition of derivative)
W - width
l - length
p - perimeter
The perimeter is 72 cm (p=72).
The length is twice the width (l=2w).
The formula for perimeter is 2w+2l=P.

Check the answer:

The length of the photo is 24 cm, the width of the photo is 12 cm.
Answer: 4
Step-by-step explanation: