Answer
Notebook each =$4
Folder each = $9
First we write out what we know
Notebook = n
Folder = f
It says a notebook is +5 than a folder so
f = n +5
It says he bought 3 notebooks and 2 folders for $30
3n + 2f = 30
Because we know from the first equation
f=n+5, we can substitute that into the second equation for f
3n + 2(n+5) = 30
3n + 2n +10 =30. Now Combine like terms
5n +10 =30. Now isolate n by subtracting 10 from both sides
5n = 20. Now isolate n by dividing both sides by 5
n = 4
Now we do the same thing to find f
We substitute the value of n (4) into the equation 3n + 2f =30
3(4) +2f =30
12 +2f =30. Now isolate f by subtracting 12 from both sides
2f = 18. Now isolate f by dividing both sides by 2
f = 9
We check our work by inserting the n and f values we found into one of the equations
n + 5 = f
4 + 5 = 9
9 = 9. It worked it equals so it’s correct
In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data:
(x - 4)² + y² = 16
Step 02:
polar form:
x = r cos (θ)
y = r sin (θ)
(r cos (θ) - 4 )² + (r sin (θ))² = 16
(r cos θ - 4)² + r² sin² θ = 16
r (r - 8 cos (θ)) = 0
r = 8 cos θ
The answer is:
r = 8 cos θ
Answer: Area of ΔABC is 2.25x the area of ΔDEF.
Step-by-step explanation: Because equilateral triangle has 3 equal sides, area is calculated as

with a as side of the triangle.
Triangle ABC is 20% bigger than the original, which means its side (a₁) measures, compared to the original:
a₁ = 1.2a
Then, its area is


Triangle DEF is 20% smaller than the original, which means its side is:
a₂ = 0.8a
So, area is


Now, comparing areas:

2.25
<u>The area of ΔABC is </u><u>2.25x</u><u> greater than the area of ΔDEF.</u>