Answer: 
Step-by-step explanation:
The perimeter of a rectangle can be calcualated with this formula:

Where "l" is the lenght and "h" is the height.
The area of a rectangle can be found with this formula:

Where "l" is the lenght and "h" is the height.
In this case we know that:

Therfore, we can susbsitute them into
and solve for "h" in order to find its value:

Find two number whose sum is 3 and whose product is -40. These are -5 and 8. Then, factorizing, we get:

The positive value is the height. Then:

Since the length is 3 centimeters greater than its height, we get that this is: Then:

Substituting values into
, we get that the perimeter is:

2/3y-2/5=5
We move all terms to the left:
2/3y-2/5-(5)=0
Domain of the equation: 3y!=0
y!=0/3
y!=0
y∈R
determiningTheFunctionDomain
2/3y-5-2/5=0
We calculate fractions
There is no solution for this equation
Answer: 39
Step-by-step explanation:
180-(39+102)
180-141
39
Answer:
<em>630 cups</em>
Step-by-step explanation:
<u>Percentages</u>
This problem is most easily solved backward, i.e., from the final data up to the beginning.
There was a new box of cups and the worker at a snack stand opened it. He first used 30 cups from the box and the second day he uses 15% of the remaining cups in the box, and we are told that represents 90 cups.
If 15% (0.15) equals 90 cups, then the number of cups before the second day was 90/0.15 = 600 cups.
On the first day, we used 30 cups, thus the original number of cups in the box was 600+30=630 cups