Can't solve system of linear equations (that need simplification first)

The first mistake I see is here:

$$9x + 6 - 6x - 12 y = x - 3$$ $$9x -6x -x - 12y = -3 +6$$

The second line should read

$$9x-6x-x-12y=-3-6$$

you forgot to invert the sign when moving $6$ to the other side of the $=$ sign.

You were equally sloppy with the second equation, when you did this:

$$5x - 6x + 8y - 15y = 2 - 4$$

We get our second simplified linear equation: $$-x -7y = 2$$

In fact, $2-4$ is not equal to $2$.


The first equation simplifies to $$2x-12y=-9$$ and the second one to $$-7y-x=-2$$

Tags:

Algebra Precalculus

Self Learning

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