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How do you find the zeros for this equation?  y=x (to the power of 2) +3x-5

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dudley10 | Student, Grade 12 | eNoter

Posted March 26, 2013 at 10:06 PM via web

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How do you find the zeros for this equation? 

y=x (to the power of 2) +3x-5

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mariloucortez | High School Teacher | (Level 3) Adjunct Educator

Posted March 26, 2013 at 11:02 PM (Answer #1)

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To solve for the zeros, set y = 0 and you'll have:

`x^2 + 3x - 5 = 0`

Then use quadratic formula: `x = (-b+-sqrt(b^2-4ac))/(2a)`

The quadratic equation above is in the form `ax^2 + bx + c = 0.`

You can now apply the formula.

a = 1

b = 3

c = -5

So, `x = (-3+-sqrt(3^2-4(1)(-5)))/((2)(1))`

      `x = (-3+-sqrt(9+20))/2`

      `x = (-3 + sqrt(29))/2`

      `x = 1.19 (rounded to two decimal position)`

      `x=(-3-sqrt(29))/2`

      `x = -4.19(rounded to two decimal position)`

Since it is a quadratic equation (with 2 as the highest exponent), you should have 2 values for x.

The roots are 1.19 and - 4.19.

 

  

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