Answer:
x = 53
y = 30
Step-by-step explanation:
Step(I):-
Given equations are
x -2y =-7 ...(I)
5x-9y =-5 ..(ii)
The matrix form AX = B
![\left[\begin{array}{ccc}1&-2\\ 5 & -9\\\end{array}\right] \left[\begin{array}{ccc}x\\y\\\end{array}\right] = \left[\begin{array}{ccc}-7\\-5\\\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%26-2%5C%5C%205%20%20%26%20-9%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx%5C%5Cy%5C%5C%5Cend%7Barray%7D%5Cright%5D%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-7%5C%5C-5%5C%5C%5Cend%7Barray%7D%5Cright%5D)
The determinant
By using Cramer's Rule
Δ₁ = ![\left[\begin{array}{ccc}-7&-2\\\\-5&-9\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-7%26-2%5C%5C%5C%5C-5%26-9%5Cend%7Barray%7D%5Cright%5D)
The determinant is Δ₁ = -9 X -7 - (10 ) = 53
x = Δ₁ / Δ
x = 53
The determinant
Δ₂ =
Δ₂ = -5 +35
y = Δ₂/Δ = 30
Answer:
Step-by-step explanation:
Answer: D. a+2s=$22
a+3s=$28
Step-by-step explanation:
Let's take a look at our variables. They are a and s, the a standing for the cost of an adult ticket and the s standing for the cost of the student ticket. In both situations, only one adutl ticket was purchased, so we start off out equations with only an a. As for the student tickets, Alex buys 2 and Jen buys 3.
a+2s
a+3s
The whole point of writing this equation is to find the cost of the tickets, so we would both equal it to the amount they spent.
a+2s=$22
a+3s=$28
X=number of adults, y= number of students
x+y=12
18x+12y=162
You can simplify the second equation by dividing by six: 3x+2y=27
Rearrange the first equation: y= 12-x. Plug y into the simplified second equation:
3x+2(12-x)=27
3x-2x+24=27
x=3.
Plug the now known x value into y=12-x. So y= 9.
Therefore, there are 3 adults and 9 students.
