Answer:
![\left \{ {{x = -15} \atop {y=3}} \right.](https://tex.z-dn.net/?f=%5Cleft%20%5C%7B%20%7B%7Bx%20%3D%20-15%7D%20%5Catop%20%7By%3D3%7D%7D%20%5Cright.)
Step-by-step explanation:
![\left \{ {{x + 5y = 0} (1) \atop {3y + 2x = -21}(2)} \right. \left \{ {{x = -5y} \atop {3y + 2x = -21}} \right. \left \{ {{x = -5y} \atop {3y + 2*(-5y) = -21}} \right. \left \{ {{x = -5y} \atop {3y - 10y = -21}} \right. \\ \left \{ {{x = -5y } \atop {-7y = -21}} \right. \left \{ {{x = -5y} \atop {y= 3 }} \right. \left \{ {{x = -5 * 3} \atop {y=3}} \right.=> \left \{ {{x=-15} \atop {y=3}} \right.](https://tex.z-dn.net/?f=%5Cleft%20%5C%7B%20%7B%7Bx%20%2B%205y%20%3D%200%7D%20%281%29%20%5Catop%20%7B3y%20%2B%202x%20%3D%20-21%7D%282%29%7D%20%5Cright.%20%3C%3D%3E%20%5Cleft%20%5C%7B%20%7B%7Bx%20%3D%20-5y%7D%20%5Catop%20%7B3y%20%2B%202x%20%3D%20-21%7D%7D%20%5Cright.%20%20%20%3C%3D%3E%20%5Cleft%20%5C%7B%20%7B%7Bx%20%3D%20-5y%7D%20%5Catop%20%7B3y%20%2B%202%2A%28-5y%29%20%3D%20-21%7D%7D%20%5Cright.%20%3C%3D%3E%20%5Cleft%20%5C%7B%20%7B%7Bx%20%3D%20-5y%7D%20%5Catop%20%7B3y%20-%2010y%20%3D%20-21%7D%7D%20%5Cright.%20%5C%5C%3C%3D%3E%20%5Cleft%20%5C%7B%20%7B%7Bx%20%3D%20-5y%20%7D%20%5Catop%20%7B-7y%20%3D%20-21%7D%7D%20%5Cright.%20%3C%3D%3E%20%5Cleft%20%5C%7B%20%7B%7Bx%20%3D%20-5y%7D%20%5Catop%20%7By%3D%203%20%7D%7D%20%5Cright.%20%3C%3D%3E%20%5Cleft%20%5C%7B%20%7B%7Bx%20%3D%20-5%20%2A%203%7D%20%5Catop%20%7By%3D3%7D%7D%20%5Cright.%3D%3E%20%5Cleft%20%5C%7B%20%7B%7Bx%3D-15%7D%20%5Catop%20%7By%3D3%7D%7D%20%5Cright.)
Answer:
![Y = 15x+ 100](https://tex.z-dn.net/?f=Y%20%3D%2015x%2B%20100)
x = 10 months
Step-by-step explanation:
Given:
Initial deposit = $100
Weakly deposit = $15
Solution:
We need to create an equation where total amount is y is equal to initial deposit plus multiplication of weakly deposit and month x, so the equation is written as.
---------(1)
Where:
Y = Total amount
x = Number of months.
Second thing we need to find the month for y = $250
Now, we substitute y = 250 in equation 1.
![250 = 15x+ 100](https://tex.z-dn.net/?f=250%20%3D%2015x%2B%20100)
![15x=250-100](https://tex.z-dn.net/?f=15x%3D250-100)
![15x =150](https://tex.z-dn.net/?f=15x%20%3D150)
![x=\frac{150}{15}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B150%7D%7B15%7D)
x = 10 months
Therefore, we need to required 10 months for $250.
Step-by-step explanation:
Take the number as x
12x-40=7x+25
collect like terms
12x-7x=25+40
5x=65(divide both sides by 5)
x=13
Therefore number is 13