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Using the quadratic formula what does x =

y=4x^2 + 6x - 2

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Sam M. | Mr. Gets ResultsMr. Gets Results
4.8 4.8 (119 lesson ratings) (119)


The number of answers in infinite, as the value of X will depend on Y.  As an example, let's say Y were equal to 7 (just because).  If Y were equal to 7, I would therefore have:

7 = 4x2 + 6x - 2. 

Now remember, the quadratic formula only works if the equation IS SET EQUAL TO ZERO.  So the first thing I have to do is subtract 7 from each side:

0 = 4x2 + 6x - 9     Hopefully, that makes sense.  It's just a little bit of algebra.  Now I can use the quadratic formula where A = 4, B = 6 and C = -9. 

Remember the quadratic formula: 
The Quadratic Formula

With that in mind, let's plug and chug!  -6 sqrt[36 - 4(4)(-9)]...all divided by 2(4)

That rounds out to -6 + squrt(180)  all divided by 8.

The simplest that gets is -3 + 3sqrt(5) all divided by 4. 

That's just if y is 7.  Remember, always set it to zero.