Answer:
The number is 12
Step-by-step explanation:
[] First, let's turn all these words into something mathematical. N will equal "my number"
-><u> If you add 12 to my number</u> and then multiply the result by 3, you will get 64 more than two-thirds of my number.
-> n + 12 <u>and then multiply the result by 3</u>, you will get 64 more than two-thirds of my number.
-> 3(n + 12), you will get 64 more than <u>two-thirds of my number</u>.
-> 3(n + 12) = <u>64 more than</u> 
-> 3(n + 12) = 64 +
[] Phew, okay. Now it is something we can solve and less scary;
[Given]
3(n + 12) = 64 +
[Distribute]
3n + 36 = 64 +
[Multiply both sides by 3]
9n + 108 = 192 + 2n
[Subtract 108 and 2n from both sides]
7n = 84
[Divide both sides by 4]
n = 12
Have a nice day!
I hope this is what you are looking for, but if not - comment! I will edit and update my answer accordingly. (ノ^∇^)
- Heather
Answer:
18 and 19
Step-by-step explanation:
<span>238 square units.
The area of a parallelogram is the base multiplied by the height. You can use any of its four sides as the base, so pick the one that is easiest to deal with. Examining the parallelogram, you'll notice that line segments AB and CD are both parallel to the x axis which makes it extremely easy to calculate the height which is 12 - (-5) = 17.
The length of AB is 13 - (-1) = 14. So the area of the parallelogram is 14 * 17 = 238</span>
Set the whole expression = to 0 and solve for x.
3x^(5/3) - 4x^(7/3) = 0. Factor out x^(5/3): x^(5/3) [3 - 4x^(2/3)] = 0
Then either x^(5/3) = 0, or 3 - 4x^(2/3) = 0.
In the latter case, 4x^(2/3) = 3.
To solve this: mult. both sides by x^(-2/3). Then we have
4x^(2/3)x^(-2/3) = 3x^(-2/3), or 4 = 3x^(-2/3). It'd be easier to work with this if we rewrote it as
4 3
--- = --------------------
1 x^(+2/3)
Then
4
--- = x^(-2/3). Then, x^(2/3) = (3/4), and x = (3/4)^(3/2). According to my 3 calculator, that comes out to x = 0.65 (approx.)
Check this result! subst. 0.65 for x in the given equation. Is the equation then true?
My method here was a bit roundabout, and longer than it should have been. Can you think of a more elegant (and shorter) solution?
Answers:
- Total equation: x+y = 80
- Legs equation: 2x+4y = 248
- How many ducks? 36
- How many cows? 44
====================================================
Further explanation:
- x = number of ducks
- y = number of cows
x+y = 80 is the total equation (ie the head count equation) since we assume each animal has 1 head, and there are 80 heads total.
That equation can be solved to y = 80-x after subtracting x from both sides.
The legs equation is 2x+4y = 248 because...
- 2x = number of legs from all the ducks only
- 4y = number of legs from all the cows only
- 2x+4y = total number of legs from both types of animals combined
We're told there are 248 legs overall, so that's how we ended up with 2x+4y = 248
------------
Let's plug y = 80-x into the second equation and solve for x.
2x+4y = 248
2x+4( y ) = 248
2x+4( 80-x ) = 248
2x+320-4x = 248
-2x+320 = 248
-2x = 248-320
-2x = -72
x = -72/(-2)
x = 36
There are 36 ducks
Now use this x value to find y
y = 80-x
y = 80-36
y = 44
There are 44 cows.
------------
Check:
36 ducks + 44 cows = 80 animals total
36*2 + 44*4 = 72 + 176 = 248 legs total
The answers are confirmed.
