+8 means that it is a positive number
-8 means that it is a negative number
I think what you mean by: {8}, is |8| which is absolute value which means no matter the answer it is the absolute value from 0 so it’s always +
If the only thing we know about x is that it is negative, we only know that -x will always be positive.
Answer: a11 = 3, a12 = 7, a21 = 1, a22 = -4
<u>Explanation:</u>
3x + 7y = 20
x - 4y = 9
A = ![\left[\begin{array}{ccc}3&7&20\\1&-4&9\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%267%2620%5C%5C1%26-4%269%5Cend%7Barray%7D%5Cright%5D)
<u>column 1 </u> <u>column 2</u>
row 1: (a11) 3 (a12) 7
row 2: (a21) 1 (a22) -4
Answer:
3
Step-by-step explanation: