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Teachers & SchoolsCAHSEE Math Algebra I: Drill 1, Problem 4. Which of the following is the solution set to the equation?

Algebra | One-Variable Equations and Inequalities |

Algebra I | Solving absolute values |

CAHSEE Math | Algebra I |

Functions | Absolute Value Functions |

Language | English Language |

For starters, let’s just ignore the absolute value piece…

…and solve for 3x minus 6 equals 21.

And add 6 to both sides...

We get 3x equals 27… so x is 9.

That’s if everything’s positive and rosy.

And since we KNOW that one of the solutions has to be 9, we can cross off A and D as potential answers.

The only question left is whether the negative 5 in choice C works as well.

So let’s… give it a spin.

And in this case we DO need to take the absolute value thing into account.

We have 3 times negative 5, which is negative 15 – then subtract 6 and we have negative 21.

But after we take the absolute value… we get positive 21.

And yeah… 21 equals 21… so negative 5 and 9 both work…

…and the answer is C.

As in, “Clear skies ahead.”