Respuesta :

Answer:

B on edge 2020

Step-by-step explanation:

By using Cramer’s Rule, the value of x is 2/7 and y is 1/2.

Cramer’s Rule;

Cramer’s Rule is defined as the determinant method to find the solution of the linear system of equations.

Given

The system of equations;

[tex]\rm 9x-2y=5\\\\-3x-4y=-4[/tex]

The Cramer's rule to find the value of x in the following system of equations.

[tex]\rm \dfrac{x}{D_1}=\dfrac{y}{D_2}=\dfrac{1}{D}[/tex]

Where;

[tex]\rm D_1=\left[\begin{array}{ccc}5&-2\\4&-4\\\end{array}\right] \\\\D_1= 5\times (-4) - 4 \times (-2)\\\\D_1=-20-(-8)\\\\D_1=-20+8\\\\D_1=-12\\\\D_2=\left[\begin{array}{ccc}9&5\\-3&-4\\\end{array}\right] \\\\D_2=9\times (-4)-5\times (-3)\\\\D_2=-36-(-15)\\\\D_1=-36+15\\\\D_1=-21\\\\D = \left[\begin{array}{ccc}9&-2\\-3&-4\\\end{array}\right] \\\\ D = 9\times(-4)-(-2)\times (-3)\\\\D=-36-6\\\\D=-42[/tex]

Therefore,

[tex]\rm \dfrac{x}{D_1}=\dfrac{y}{D_2}=\dfrac{1}{D}\\\\\rm \dfrac{x}{-12}=\dfrac{y}{-21}=\dfrac{1}{-42}\\\\ \dfrac{x}{-12}=\dfrac{1}{-42}\\\\ -42x=-12\\\\x=\dfrac{-12}{-42}\\\\x=\dfrac{2}{7}\\\\\dfrac{y}{-21}=\dfrac{1}{-42}\\\\ -42y=-21\\\\y=\dfrac{-21}{-42}\\\\y=\dfrac{1}{2}[/tex]

Hence, by using Cramer’s Rule, the value of x is 2/7 and y is 1/2.

To know more about Cramer’s Rule click the link given below.

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