Question

Using Cramer's Rule, what are the values of x and y in the solution to the system of linear equations below? -2x + 3y + z = 7 -4x - y -2z = 15 x + 2y +3z = -7

Answer 1

x = -3

y = 1

z = -2

Explanation:

-2x + 3y + z = 7

-4x - y -2z = 15

x + 2y +3z = -7

|-2 3 1|

|-4 -1 -2|

|1 2 3|

Determinant of this from online determinant calculator is;

D = 21

For Dx, we have;

|7 3 1|

|15 -1 -2|

|-7 2 3|

Determinant of this from online determinant calculator is;

Dx = -63

For Dy, we have;

|-2 7 1|

|-4 15 -2|

|1 -7 3|

Determinant of this from online determinant calculator is;

Dy = 21

For Dz, we have;

|-2 3 7|

|-4 -1 15|

|1 2 -7|

Determinant of this from online determinant calculator is;

Dz = -42

From creamers rule;

x = Dx/D

y = Dy/d

z = Dz/d

Thus;

x = -63/21

x = -3

y = 21/21

y = 1

z = -42/21

z = -2

Thus,

x = -3

y = 1

z = -2