Cramer's rule:

Which equation can be used to determine x-value of the solution in the system of linear equations below?

-2x+14y=148
3x+5y=246

a. 148 14
246 5
--------------- = 52
-2 14
3 5

b. -2 148
3 246
--------------- = 18
-2 14
3 5

c. 148 14
246 5
-------------- = 18
-2 14
3 5

d. -2 148
3 246
--------------- = 52
-2 14
3 5

Respuesta :

Answer:

[tex]a. \quad\dfrac{\left|\begin{array}{cc}148&14\\246&5\end{array}\right|}{\left|\begin{array}{cc}-2&14\\3&5\end{array}\right|}=52[/tex]

Step-by-step explanation:

To find the value of x, Cramer's rule says you replace the x-coefficients with the equation constants to form the matrix whose determinant is the numerator of the fraction. The denominator is the determinant of the matrix of coefficients. The equation constants are 148 and 246, so you expect to find those in the first column of the numerator (answer choices A and C).

[tex]\dfrac{\left|\begin{array}{cc}148&14\\246&5\end{array}\right|}{\left|\begin{array}{cc}-2&14\\3&5\end{array}\right|}=\dfrac{-2704}{-52}=52[/tex]

The calculation is carried out correctly only in answer choice A.

The x-value of the solution for the system of equations

[tex]\frac{\begin{vmatrix}148 \;\; 14\\ 246\;\;\; 5\end{vmatrix}}{\begin{vmatrix}-2 \;\; 14\\ 3\;\;\; 5\end{vmatrix}} =52[/tex]

System of linear equations

Linear equation with two variables is of the form [tex]ax+by=c[/tex]

system of linear equations is a set of two linear equations with two variables.

Given system of equations

[tex]-2x+14y=148\\3x+5y=246[/tex]

Cramer's rule

For system of linear equations of the form

[tex]ax+by=e\\cx+dy=f[/tex]

the x value is

[tex]\frac{\begin{vmatrix}e\;\; b\\ f\;\;\; d\end{vmatrix}}{\begin{vmatrix}a \;\; b\\ c\;\;\; d\end{vmatrix}}[/tex]

We apply Cramer's rule to find out the x value .

To find the x value of the system of equation , we take the determinant of x matrix divide by the determinant of coefficient matrix.

Coefficient matrix contains coefficients of x  and y

[tex]\begin{vmatrix}-2 \;\; 14\\ 3\;\;\; 5\end{vmatrix}[/tex]

For determinant of x -value of matrix , we replace coefficient of x by the constants.

[tex]\begin{vmatrix}148 \;\; 14\\ 246\;\;\; 5\end{vmatrix}[/tex]

To find out x values we divide determinant of x value by the coefficient matrix

[tex]\frac{\begin{vmatrix}148 \;\; 14\\ 246\;\;\; 5\end{vmatrix}}{\begin{vmatrix}-2 \;\; 14\\ 3\;\;\; 5\end{vmatrix}}[/tex]

Now find out the value of determinant to simplify it

[tex]\frac{\begin{vmatrix}148 \;\; 14\\ 246\;\;\; 5\end{vmatrix}}{\begin{vmatrix}-2 \;\; 14\\ 3\;\;\; 5\end{vmatrix}} \\\frac{148\cdot 5 - (14\cdot 246)}{(-2\cdot 5)-(14\cdot 3)} =\frac{-2704}{-52} =52\\\frac{\begin{vmatrix}148 \;\; 14\\ 246\;\;\; 5\end{vmatrix}}{\begin{vmatrix}-2 \;\; 14\\ 3\;\;\; 5\end{vmatrix}} =52[/tex]

The x-value of the solution for the system of equations

[tex]\frac{\begin{vmatrix}148 \;\; 14\\ 246\;\;\; 5\end{vmatrix}}{\begin{vmatrix}-2 \;\; 14\\ 3\;\;\; 5\end{vmatrix}} =52[/tex]

Learn more about Cramer's rule here :

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