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
Hello from MrBillDoesMath!
Answer:
36 degrees
Discussion:
The attachment shows calculated angles in red. As a straight line has 180 degrees the missing angle at A is 180 - 72 = 108 degrees (shown in red). The missing angle at B is 180 - 144 = 36. As a triangle has 180 degrees.
x + 108 + 36 = 180 => as 180 + 36 = 144
x + 144 = 180 => subtract 144 form both sides
x = 180 - 144 = 36
Thank you,
MrB
Answer:

Step-by-step explanation:
I'm sorry that I cannot show you my work as the equation generator does not support dividing polynomials.
i'm thinking yes how ever tou want to do it because i am only in 4th grade
Answer:
C) 154
Step-by-step explanation:
This is the formula A=πr^2 so, 3.14*7^2=153.86 so glad to help you this is my 100th math q!!!