Expert: Sherman D. - 5/18/2006

Question
i have a question about the following expression
y=2(x)squared -17(x)-19 after the formula x=b over2(a)and i also dont understand how to graph it to get the parabola

Answer
y = 2x^2 - 17x - 19

If you are talking about

x = (-b ± sqrt(b^2 - 4ac))/2a
x = (-(-17) ± sqrt((-17)^2 - 4(2)(-19)))/2(2)
x = (17 ± sqrt(289 + 152))/4
x = (17 ± sqrt(441))/4
x = (17 ± 21)/4
x = (38/4) or (-3/4)
x = (19/2) or (-3/4)

The factored form would be

(2x - 19)(4x + 3)

For a graph, you can go to http://www.calculator.com/calcs/GCalc.html
type in 2x^2 - 17x - 19

Keep in mind, if you have -x^2, then you will have to type it in like -(x^2), or it will take it as (-x)^2.

also try www.quickmath.com, this website will take -x^2 as the way it should be used.