To find the matrix A, took all the numeric coefficient of the variables, the first column is for x, the second column for y, the third column for z and the last column for w:

$A=\left[\begin{array}{cccc}1&1&2&2\\-7&-3&5&-8\\4&1&1&1\\3&7&-1&1\end{array}\right]$

And the vector B is formed with the solution of each equation of the system: $b=\left[\begin{array}{c}3\\-3\\6\\1\end{array}\right]$

To apply the Cramer's rule, take the matrix A and replace the column assigned to the variable that you need to solve with the vector b, in this case, that would be the second column. This new matrix is going to be called $A_{2}$ .

$A_{2}=\left[\begin{array}{cccc}1&3&2&2\\-7&-3&5&-8\\4&6&1&1\\3&1&-1&1\end{array}\right]$

The value of y using Cramer's rule is:

$y=\frac{det(A_{2}) }{det(A)}$

Find the value of the determinant of each matrix, and divide:

$y==\frac{\left|\begin{array}{cccc}1&3&2&2\\-7&-3&5&-8\\4&6&1&1\\3&1&-1&1\end{array}\right|}{\left|\begin{array}{cccc}1&1&2&2\\-7&-3&5&-8\\4&1&1&1\\3&7&-1&1\end{array}\right|} =\frac{158}{-579}$

$y=-\frac{158}{579}$

7 0

3 years ago

H. Salaries of Ravi and Sumit are in the ratio 2 : 3. If the salary of each is increased by Rs. 4000, the new ratio becomes 40 :

frutty [35]

Answer:

so here is the answer hope it helps

8 0

2 years ago

Please I need answer fast will give brainliest

Sonbull [250]

Point slope is y-y1=m(x-x1)
Keep y and x as they are (do not plug anything in for those).
Variable m is the slope.
x1 and y1 are part of the point, which is in (x, y) form.
With the information given, plug each into the equation.
m= 2 (It's the slope)
x1=-8
y1=5
Put these variables into the equation like this-
y-5=2(x--8)
The two negatives cancel out (between x and 8) so your final answer is-
y-5=2(x+8)

6 0

3 years ago