X by itself is 1, otherwise it is the number to the left
10x - 4y = 5 (if it requires shorten)
Step-by-step explanation:
x + y/5 - 1 = y - x
<=> (5x + y - 1.5)/5 = 5(y - x)/5
<=> 5x + y - 5 = 5y - 5x
<=> 5x + 5x + y - 5y = 5
<=> 10x - 4y = 5
Answer:
Judy = $5/hr
Ben = $4/hr
Step-by-step explanation:
Judy's hours at work - x
Ben's hours at work - y
8x + 10y = 80
9x + 5y = 65
Given these two equations above, we get:
10y = 80 - 8x, which means y = 8 - 0.8x.
Substitute y in the second equation with 8 - 0.8x, so we have:
9x + 5 (8 - 0.8x) = 65
9x + 40 - 4x = 65
5x = 25
x = 5
Come back to the first equation, substitute x:
8*5 + 10y = 80
10y = 80 - 40
y = 4
The second matrix ![\left[\begin{array}{ccc}-6&3&12\\0&15&-24\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-6%263%2612%5C%5C0%2615%26-24%5Cend%7Barray%7D%5Cright%5D)
represents the triangle dilated by a scale factor of 3.
Step-by-step explanation:
Step 1:
To calculate the scale factor for any dilation, we divide the coordinates after dilation by the same coordinated before dilation.
The coordinates of a vertice are represented in the column of the matrix. Since there are three vertices, there are 2 rows with 3 columns. The order of the matrices is 2 × 3.
Step 2:
If we form a matrix with the vertices (-2,0), (1,5), and (4,-8), we get
![\left[\begin{array}{ccc}-2&1&4\\0&5&-8\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-2%261%264%5C%5C0%265%26-8%5Cend%7Barray%7D%5Cright%5D)
The scale factor is 3, so if we multiply the above matrix with 3 throughout, we will get the matrix that represents the vertices of the triangle after dilation.
Step 3:
The matrix that represents the triangle after dilation is given by
![3\left[\begin{array}{ccc}-2&1&4\\0&5&-8\end{array}\right] = \left[\begin{array}{ccc}3(-2)&3(1)&3(4)\\3(0)&3(5)&3(-8)\end{array}\right] = \left[\begin{array}{ccc}-6&3&12\\0&15&-24\end{array}\right]](https://tex.z-dn.net/?f=3%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-2%261%264%5C%5C0%265%26-8%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%28-2%29%263%281%29%263%284%29%5C%5C3%280%29%263%285%29%263%28-8%29%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-6%263%2612%5C%5C0%2615%26-24%5Cend%7Barray%7D%5Cright%5D)
This is the second option.
Recall that A = 1/2bh.
We are given that h = 4+2b
So, putting it all together:
168 = 1/2 b(4+2b)
168 = 1/2(4b + 2b^2)
168 = 2b + b^2
b^2 + 2b - 168 = 0.
Something that multiplies to -168 and adds to 2? There's a trick to this.
Notice 13^2 = 169. So, it's more than likely in the middle of the two numbers we're trying to find. So let's try 12 and 14. Yep. 12 x 14 = 168. So this factors into (b+14)(b-12) So b = -14 or b =12. Is it possible to have a negative length on a base? No. So 12 must be our answer.
Let's check this. If 12 is our base, then according to our problem, 2*12 + 4 would be our height... or 28. so what is 12 * 28 /2?
196. Check.
Hope this helped!
