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Use the given roots to write the equation in factored form. Then multiply and simplify to obtain the expression in standard form.
J
We want to determine which of the given quadratic equations has the roots 12 and 13. To do so, we can write a quadratic equation in factored form using the given roots. Then we will rewrite it to be in standard form by multiplying the factors.
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Factored Form: & a(x- p)(x- q)=0
Standard Form: & ax^2+ bx+ c=0
a= 6
Split into factors
Commutative Property of Multiplication
Distribute 2
Distribute 3
Note that we obtained the equation from option J. Therefore, J is the correct answer.
| Equation | Substitute | Evaluate |
|---|---|---|
| 5x^2-5x-2=0 | 5( 1/2)^2-5( 1/2)-2? =0 | - 13/4 ≠0 |
| 5( 1/3)^2-5( 1/3)-2? =0 | - 28/9≠0 | |
| 5x^2-5x+1=0 | 5( 1/2)^2-5( 1/2)+1? =0 | - 1/4≠0 |
| 5( 1/3)^2-5( 1/3)+1? =0 | - 1/9≠0 | |
| 6x^2+5x-1=0 | 6( 1/2)^2+5( 1/2)-1? =0 | 3≠0 |
| 6( 1/3)^2+5( 1/3)-1? =0 | 4/3≠0 | |
| 6x^2-5x+1=0 | 6( 1/2)^2-5( 1/2)+1? =0 | 0=0 |
| 6( 1/3)^2-5( 1/3)+1? =0 | 0=0 |
We obtained true statements only for the equation 6x^2-5x+1=0. Therefore, this is the only equation that has the roots 12 and 13 and our answer is correct.