SOLUTION: how do you do this (-bą√(b^2-4ac)2a

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Question 425871: how do you do this (-bą√(b^2-4ac)2a
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
sandard form of a quadratic equation is:
ax^2 + bx + c = 0

a is the coefficient of the x^2 term
b is the coefficient of the x term
c is the constant term

a,b,c are use in he equation x = (-bą√(b^2-4ac)2a

you replace a,b,c in the equation with the value you derived from the standard form of your equation.

that provides you with the x value of when the graph of the equation crosses the x axis.

an example

your equation is x^2 + 3x - 10 = 0

this equation is already in standard form of ax^2 + bx + c = 0

this gives you:

a = 1
b = 3
c = -10

plug those values into your quadratic equation and you get:

x = %28%28-3%29+%2B-+sqrt%28%28-3%29%5E2+-+%284%2A1%2A%28-10%29%29%29%29%2F%282%2A1%29

simplify this equation to get:

x = %28%28-3%29+%2B-+7%29%2F2

solve for x to get:

x = -5 or x = +2

those are the roots of your equation.

a graph of your equation looks like this:

graph%28600%2C600%2C-10%2C10%2C-15%2C15%2Cx%5E2+%2B+3x+-+10%29

you can see that the graph crosses the x-axis at x = -5 and at x = 2