Answer:
D
Step-by-step explanation:
Answer:
![\left[\begin{array}{cc}3&9\\5&-2\end{array}\right] +\left[\begin{array}{cc}6&0\\-8&4\end{array}\right]=\left[\begin{array}{cc}9&9\\-3&2\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D3%269%5C%5C5%26-2%5Cend%7Barray%7D%5Cright%5D%20%2B%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D6%260%5C%5C-8%264%5Cend%7Barray%7D%5Cright%5D%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D9%269%5C%5C-3%262%5Cend%7Barray%7D%5Cright%5D)
Step-by-step explanation:
To add matrices, we add the corresponding components.
The given matrices is
![\left[\begin{array}{cc}3&9\\5&-2\end{array}\right] +\left[\begin{array}{cc}6&0\\-8&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D3%269%5C%5C5%26-2%5Cend%7Barray%7D%5Cright%5D%20%2B%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D6%260%5C%5C-8%264%5Cend%7Barray%7D%5Cright%5D)
We add the corresponding components to get;
![\left[\begin{array}{cc}3&9\\5&-2\end{array}\right] +\left[\begin{array}{cc}6&0\\-8&4\end{array}\right]=\left[\begin{array}{cc}3+6&9+0\\5+-8&-2+4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D3%269%5C%5C5%26-2%5Cend%7Barray%7D%5Cright%5D%20%2B%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D6%260%5C%5C-8%264%5Cend%7Barray%7D%5Cright%5D%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D3%2B6%269%2B0%5C%5C5%2B-8%26-2%2B4%5Cend%7Barray%7D%5Cright%5D)
We simplify to get:
![\left[\begin{array}{cc}3&9\\5&-2\end{array}\right] +\left[\begin{array}{cc}6&0\\-8&4\end{array}\right]=\left[\begin{array}{cc}9&9\\-3&2\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D3%269%5C%5C5%26-2%5Cend%7Barray%7D%5Cright%5D%20%2B%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D6%260%5C%5C-8%264%5Cend%7Barray%7D%5Cright%5D%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D9%269%5C%5C-3%262%5Cend%7Barray%7D%5Cright%5D)
<em>Answer</em>
B) y = 3
<em>Step-by-step explanation</em>
Given the system of equations:

Isolating x from equation 1:

Substituting equation 3 into equation 2 and solving for y:

So you subtract, 27-22. 27-22 is equal to 5. So, John will buy 5 kinds of T- Shirts.