Answer:
The first step is to replace the y in y-x=15 with 7x (we can do this because the first equation tells us that they're equal)
solve and get
(2.5,17.5)
or x= 2.5 y=17.5
Step-by-step explanation:
The first step is to recognize that y=7x which means that we can just replace the y in the second equation with 7x
7x-x=15
6x=15
x=2.5
Then we can solve for y
y=7(2.5)
y=17.5
Answer: The required characteristic polynomial of the given matrix A is 
Step-by-step explanation: We are given to find the characteristic polynomial of the following 3 × 3 matrix A with unknown variable x :
![A=\left[\begin{array}{ccc}0&0&1\\4&-3&4\\-2&0&-3\end{array}\right].](https://tex.z-dn.net/?f=A%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%260%261%5C%5C4%26-3%264%5C%5C-2%260%26-3%5Cend%7Barray%7D%5Cright%5D.)
We know that
for any square matrix M, the characteristic polynomial is given by
where I is an identity matrix of same order as M.
Therefore, the characteristic polynomial of matrix A is
![|A-xI|=0\\\\\\\Rightarrow \left|\left[\begin{array}{ccc}0&0&1\\4&-3&4\\-2&0&-3\end{array}\right]-x\left[\begin{array}{ccc}1&0&0\\0&1&0\\0&0&1\end{array}\right]\right|=0\\\\\\\Rightarrow \left|\left[\begin{array}{ccc}-x&0&1\\4&-3-x&4\\-2&0&-3-x\end{array}\right] \right|=0\\\\\\\Rightarrow -x(3+x)^2+1(0-6-2x)=0\\\\\Rightarrow (x+3)(-3x-x^2-2)=0\\\\\Rightarrow (x+3)(x^2+3x+2)=0\\\\\Rightarrow x^3+6x+11x+6=0.](https://tex.z-dn.net/?f=%7CA-xI%7C%3D0%5C%5C%5C%5C%5C%5C%5CRightarrow%20%5Cleft%7C%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D0%260%261%5C%5C4%26-3%264%5C%5C-2%260%26-3%5Cend%7Barray%7D%5Cright%5D-x%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%260%260%5C%5C0%261%260%5C%5C0%260%261%5Cend%7Barray%7D%5Cright%5D%5Cright%7C%3D0%5C%5C%5C%5C%5C%5C%5CRightarrow%20%5Cleft%7C%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D-x%260%261%5C%5C4%26-3-x%264%5C%5C-2%260%26-3-x%5Cend%7Barray%7D%5Cright%5D%20%5Cright%7C%3D0%5C%5C%5C%5C%5C%5C%5CRightarrow%20-x%283%2Bx%29%5E2%2B1%280-6-2x%29%3D0%5C%5C%5C%5C%5CRightarrow%20%20%28x%2B3%29%28-3x-x%5E2-2%29%3D0%5C%5C%5C%5C%5CRightarrow%20%28x%2B3%29%28x%5E2%2B3x%2B2%29%3D0%5C%5C%5C%5C%5CRightarrow%20x%5E3%2B6x%2B11x%2B6%3D0.)
Thus, the required characteristic polynomial of the given matrix A is
Multiply the 2 mixed numbers to get your answer because area is length times with . I am not so sure but comment and tell me if you got it right or wrong.
Answer:
.434
Step-by-step explanation:
Hi!
Given the ratio of boys to girls, which is 6/9, we can find the number of boys in a total of 75 students like this:
(6/9) * 75 = (6*75)/9 = 450/9 = 50
There are 50 boys.
Hope this helps!
