Question 237429
How would you solve the problem below using Cramer's Rule:

x+3y=-4
y+x=0

First switch x and y for y + x = 0.

x + 3y = -4
x + y = 0

We need the discriminant D, the discriminant of x written Dx and the discriminant of y written Dy.

D = 1 x 1 - 1 x 3

D = 1 - 3

D = -2

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We now find Dx.


Dx = -4 x 1 - 0 x 3

Dx = -4 - 0

Dx = -4

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We now find Dy.

Dy = -4 x 1 - 1 x 0

Dy = -4 - 0

Dy = -4

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We now divided Dx and Dy by D individually.

Dx/D = x coordinate.

Dy/D = y coordinate.


x = -4/-2

x = 2.

y = -4/-2

y = 2

The solution to this system of linear equations in two variables is the point
(2, 2).

At that point, both equations cross each other.