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Solving Quadratic Equations by Factoring  Problem 1
Alissa Fong
Alissa Fong
MA, Stanford University
Teaching in the San Francisco Bay Area
Alissa is currently a teacher in the San Francisco Bay Area and Brightstorm users love her clear, concise explanations of tough concepts
Here's a problem that I want to solve by factoring. So even if I don't know what solve means I know I’m going to have to start this problem by factoring. Since both of these terms have an x I’m going to factor out the greatest common factor which is x, it’s going to start looking like this. Like undistributing. X times what gives me x squared? And then I need x times what gives me 4x here we go so that's my factored form of that binomial.
Next thing I’m going to do in order to solve, solve means find what x values make the statement true. So what I’m going to do in order to do that is use this 0 product property that tells me that if the product of two things is equal to 0 then either of that first guys is equal to 0 or the second guy is equal to 0.
That's already going to be one of my solutions if x is 0 that should be equal to 0.My other solution is going to be 4. Because if I plug in 4 here and I do out the math I should get 0. I'm going to check just a little really quickly just to make sure.
The way to check is by substituting the x value to this original problem. Is it true that 0 squared plus 4 times 0 is 0? Yeah 0 plus 0 equals 0. Is it true that 4times itself plus 4 times 4 is equal to 0? It’s kind of messy plus 4 times 4 is it true that 16 take away 16 equals 0? Yeah that's right.
That's how I know I have my two correct solutions. So when you’re asked to solve something by factoring factor out your binomial trinomial looking for greatest common factor or by using factoring techniques then set each one equal to 0. And lastly be sure to check your work because there's no reason why you want to get these problems wrong because they are not too difficult.
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Alissa Fong
M.A. in Secondary Mathematics, Stanford University
B.S., Stanford University
Alissa has a quirky sense of humor and a relatable personality that make it easy for students to pay attention and understand the material. She has all the math tips and tricks students are looking for.
Your tutorials are good and you have a personality as well. I hope you have more advanced college level stuff, because I like the way you teach.”
Thanks alot for such great lectures... I never found learning this easier ever before... keep up the great work.... :)”
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Sample Problems (22)
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Solving Quadratic Equations by Factoring
Problem 1 14,563 viewsSolve by factoring:
x² + 4x = 0 
Solving Quadratic Equations by Factoring
Problem 2 11,802 viewsSolve by factoring:
x² + 2x = 15 
Solving Quadratic Equations by Factoring
Problem 3 10,666 viewsSolve by factoring:
x² + 6x + 9 = 0 
Solving Quadratic Equations by Factoring
Problem 4 10,618 viewsSolve by factoring:
3x² − 18x = 27 
Solving Quadratic Equations by Factoring
Problem 5 1,403 views 
Solving Quadratic Equations by Factoring
Problem 6 1,411 views 
Solving Quadratic Equations by Factoring
Problem 7 1,223 views 
Solving Quadratic Equations by Factoring
Problem 8 1,194 views 
Solving Quadratic Equations by Factoring
Problem 9 1,179 views 
Solving Quadratic Equations by Factoring
Problem 10 1,221 views 
Solving Quadratic Equations by Factoring
Problem 11 1,102 views 
Solving Quadratic Equations by Factoring
Problem 12 1,103 views 
Solving Quadratic Equations by Factoring
Problem 13 1,099 views 
Solving Quadratic Equations by Factoring
Problem 14 1,238 views 
Solving Quadratic Equations by Factoring
Problem 15 1,045 views 
Solving Quadratic Equations by Factoring
Problem 16 428 views 
Solving Quadratic Equations by Factoring
Problem 17 456 views 
Solving Quadratic Equations by Factoring
Problem 18 399 views 
Solving Quadratic Equations by Factoring
Problem 19 447 views 
Solving Quadratic Equations by Factoring
Problem 20 427 views 
Solving Quadratic Equations by Factoring
Problem 21 418 views 
Solving Quadratic Equations by Factoring
Problem 22 352 views
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