# SAT Math 4.5 Algebra and Functions

###### Recommendation

### Want a study guide too?

SAT Math 4.5 Algebra and Functions

Algebra | Functions |

Algebra and Functions | Solving Quadratic Equations by Factoring |

Functions | Basics of Functions Using New Definitions |

Language | English Language |

Passport to Advanced Math | Systems of quadratic and linear equations |

Product Type | SAT Math |

SAT Math | Algebra and Functions |

### Transcript

Is it just us are you seeing dollar signs?

So we're given that x $ y equals the square root of x squared minus y squared.

So, 13 $ y is the square root of 13 squared minus y squared.

The given information tells us that 13 $ y equals 5.

This can be written as the equation square root of 13 squared minus y squared equals 5.

This gives us square root of 169 minus y squared equals 5.

Let’s get rid of the square root by squaring both sides.

This gives us 169 minus y squared equals 25.

We add y squared to both sides, then subtract 25 from both sides to get 144 equals y squared.

Now we can take the square root of 144 to get y equals 12.

BUT…we have to remember that negative 12 is also an answer, since a negative, when

squared, is positive.

The answer is (E).