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## SAT

### Unit 10: Lesson 2

Passport to advanced mathematics- Solving quadratic equations — Basic example
- Solving quadratic equations — Harder example
- Interpreting nonlinear expressions — Basic example
- Interpreting nonlinear expressions — Harder example
- Quadratic and exponential word problems — Basic example
- Quadratic and exponential word problems — Harder example
- Manipulating quadratic and exponential expressions — Basic example
- Manipulating quadratic and exponential expressions — Harder example
- Radicals and rational exponents — Basic example
- Radicals and rational exponents — Harder example
- Radical and rational equations — Basic example
- Radical and rational equations — Harder example
- Operations with rational expressions — Basic example
- Operations with rational expressions — Harder example
- Operations with polynomials — Basic example
- Operations with polynomials — Harder example
- Polynomial factors and graphs — Basic example
- Polynomial factors and graphs — Harder example
- Nonlinear equation graphs — Basic example
- Nonlinear equation graphs — Harder example
- Linear and quadratic systems — Basic example
- Linear and quadratic systems — Harder example
- Structure in expressions — Basic example
- Structure in expressions — Harder example
- Isolating quantities — Basic example
- Isolating quantities — Harder example
- Function notation — Basic example
- Function notation — Harder example

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# Solving quadratic equations — Basic example

Watch Sal work through a basic Solving quadratic equations problem.

## Video transcript

- [Instructor] What are all the solutions to the equation above? So we have four x squared is equal to 52. Well if we wanna solve for x, we can just divide both sides by four. And then we get x squared is equal to 52 divided by four is 13. So x could be equal to, if
x squared is equal to 13, then that means x could be
the positive or negative square root of 13, so
x is going to be equal to the positive or
negative square root of 13. And you could check your answer. Take positive 13, if you take, or take positive square root of 13. Well, if you square it,
you're gonna get 13. And them multiply it times
four, you're gonna get 52. Take the negative square root of 13, well when you square it,
you're going to get 13, 'cause a negative times
a negative is a positive. And then you multiply it times
four and you're gonna get 52. So x could be negative square root of 13 and/or x could be, or
the two solutions are x is the negative square root of 13 and x is equal to the
positive square root of 13. So that's our choice right over there.