Answer: 7x + 70
Step-by-step explanation:
Second one, and can I have brainelist,please, and thanks
Answer:
<h2>$87.32</h2>
Step-by-step explanation:
Step one:
given data
we are told that the initial bill is $74
thereafter they gave a tip worth 18% of the bill
let us compute what 18% of $74 will amount to
Step two:
=18/100*74
=0.18*74
=$13.32
The added expenses is $13.32
Hence the total cost is
the initial bill plus the tip
=74+13.32
=$87.32
The answer to your question is -3
Answer: The determinant of the coefficient matrix is -15 and x = 3, y = 4, z = 1.
Step-by-step explanation: The given system of linear equations is :
![2x+y+3z=13~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)\\\\x+2y=11~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(ii)\\\\3x+z=10~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(iii)](https://tex.z-dn.net/?f=2x%2By%2B3z%3D13~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~%28i%29%5C%5C%5C%5Cx%2B2y%3D11~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~%28ii%29%5C%5C%5C%5C3x%2Bz%3D10~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~%28iii%29)
We are given to find the determinant of the coefficient matrix and to find the values of x, y and z.
The determinant of the co-efficient matrix is given by
![D=\begin{vmatrix}2 & 1 & 3\\ 1 & 2 & 0\\ 3 & 0 & 1\end{vmatrix}=2(2-0)+1(0-1)+3(0-6)=4-1-18=-15.](https://tex.z-dn.net/?f=D%3D%5Cbegin%7Bvmatrix%7D2%20%26%201%20%26%203%5C%5C%201%20%26%202%20%26%200%5C%5C%203%20%26%200%20%26%201%5Cend%7Bvmatrix%7D%3D2%282-0%29%2B1%280-1%29%2B3%280-6%29%3D4-1-18%3D-15.)
Now, from equations (ii) and (iii), we have
![x+2y=11~~~~~\Rightarrow y=\dfrac{11-x}{2}~~~~~~~~~~~~~~~~~~~~~~~~~~(iv)\\\\\\3x+z=10~~~~~~\Rightarrow z=10-3x~~~~~~~~~~~~~~~~~~~~~~~~~(v)](https://tex.z-dn.net/?f=x%2B2y%3D11~~~~~%5CRightarrow%20y%3D%5Cdfrac%7B11-x%7D%7B2%7D~~~~~~~~~~~~~~~~~~~~~~~~~~%28iv%29%5C%5C%5C%5C%5C%5C3x%2Bz%3D10~~~~~~%5CRightarrow%20z%3D10-3x~~~~~~~~~~~~~~~~~~~~~~~~~%28v%29)
Substituting the value of y and z from equations (iv) and (v) in equation (i), we get
![2x+y+3z=13\\\\\Rightarrow 2x+\dfrac{11-x}{2}+3(10-3x)=13\\\\\Rightarrow 4x+11-x+60-18x=26\\\\\Rightarrow -15x+71=26\\\\\Rightarrow -15x=26-71\\\\\Rightarrow -15x=-45\\\\\Rightarrow x=3.](https://tex.z-dn.net/?f=2x%2By%2B3z%3D13%5C%5C%5C%5C%5CRightarrow%202x%2B%5Cdfrac%7B11-x%7D%7B2%7D%2B3%2810-3x%29%3D13%5C%5C%5C%5C%5CRightarrow%204x%2B11-x%2B60-18x%3D26%5C%5C%5C%5C%5CRightarrow%20-15x%2B71%3D26%5C%5C%5C%5C%5CRightarrow%20-15x%3D26-71%5C%5C%5C%5C%5CRightarrow%20-15x%3D-45%5C%5C%5C%5C%5CRightarrow%20x%3D3.)
From equations (iv) and (v), we get
![y=\dfrac{11-3}{2}=4,\\\\z=10-3\times3=1.](https://tex.z-dn.net/?f=y%3D%5Cdfrac%7B11-3%7D%7B2%7D%3D4%2C%5C%5C%5C%5Cz%3D10-3%5Ctimes3%3D1.)
Thus, the determinant of the coefficient matrix is -15 and x = 3, y = 4, z = 1.