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
3/2x=6 answer:4
X/2=-4 answer: -8
-5x=26 answer:-5.2
X/-7.2=-4 answer: 28.8
Answer:
30 students
Step-by-step explanation:
40% boys and 12 boys so 60% is girls
40/100=12/x
x=30
30-12 is 18
so 30 students, 12 boys, and 18 girls.
Answer= 11
Explanation= i plugged it into a calculator