Answer:
Step-by-step explanation:
y - 9 = 3(x - 0)
y - 9 = 3x - 0
y = 3x + 9
The missing coordinate r is 11.
Solution:
Given points are (–15, 1) and (–7, r).
![x_{1}=-15, x_{2}=-7, y_{1}=1 \text { and } y_{2}=7](https://tex.z-dn.net/?f=x_%7B1%7D%3D-15%2C%20x_%7B2%7D%3D-7%2C%20y_%7B1%7D%3D1%20%5Ctext%20%7B%20and%20%7D%20y_%7B2%7D%3D7)
Slope (m) = ![\frac{5}{4}](https://tex.z-dn.net/?f=%5Cfrac%7B5%7D%7B4%7D)
<u>To find the missing coordinate r:</u>
Slope formula:
![$m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$](https://tex.z-dn.net/?f=%24m%3D%5Cfrac%7By_%7B2%7D-y_%7B1%7D%7D%7Bx_%7B2%7D-x_%7B1%7D%7D%24)
Substitute the given values in the formula.
![$\frac{5}{4}=\frac{r-1}{-7-(-15)}](https://tex.z-dn.net/?f=%24%5Cfrac%7B5%7D%7B4%7D%3D%5Cfrac%7Br-1%7D%7B-7-%28-15%29%7D)
![$\frac{5}{4}=\frac{r-1}{-7+15}](https://tex.z-dn.net/?f=%24%5Cfrac%7B5%7D%7B4%7D%3D%5Cfrac%7Br-1%7D%7B-7%2B15%7D)
![$\frac{5}{4}=\frac{r-1}{8}](https://tex.z-dn.net/?f=%24%5Cfrac%7B5%7D%7B4%7D%3D%5Cfrac%7Br-1%7D%7B8%7D)
Do cross multiplication.
![8 \times 5=4(r-1)](https://tex.z-dn.net/?f=8%20%5Ctimes%205%3D4%28r-1%29)
40 = 4r – 4
Add 4 on both side of the equation.
44 = 4r
Divide by 4 on both side of the equation.
11 = r
⇒ r = 11
Hence the missing coordinate r is 11.
Answer: 6 x 8=48
Step-by-step explanation:
The 114 represents 80% of the total price before the sale. You would set up your equation as
Cost Price * 80% = Sale Price.
Sale Price = 114
80% = 80/100 = 0.8
Cost Price = 114/0.8
Cost Price = 142.50 which is the price before the deduction. You can confirm this by taking 20% of 142.50 and subtracting it form 142.50
20% * 142.50
20/100 * 142.50
2850/100
28.50
Now subtract 28.50 from 142.50
142.50 - 28.50 = 114 which is just what you might expect.