X= PLUS OR MINUS THE SQUARE ROOT OF B SQUARED MINUS 4 AC ALL OVER 2A
2006-12-31 12:54:17 · 6 answers · asked by GEORGE M 1 in Science & Mathematics ➔ Mathematics
that's part of the quadratic formula, only you're missing the -B.
If you have a quadratic equation of the form Ax^2 + Bx + C = 0, plug the A, B, C into the formula and get the solutions.
This formula can be derived by completing the square on the general form. It will give you answers even when you can't factor, even if the answers are complex numbers or double roots. So why bother factor? Why not just use this formula all the time? Well, often it's easier to factor (once you understand factoring) and this formula is a bit more work. More work means more time on the test and more chances of making mistakes.
Here's an example:
x^2 + 2x + 3 = 0
This won't factor, since there are no two whole numbers that you can multiply to get 3 and add to get 2. So plug it into the quadratic formula, with A=1, B=2. C=3
x = (-2 +/ (sqrt (2^2 - (4x1x3)))/(2x1) =
(-2 +/- sqrt (4 - 12))/2 = (-2 +/- sqrt(-8))/2 =
(-2 +/- 2i sqrt 2)/2 = -1 +/- i sqrt 2
If we'd started out with sometihng that does factor, the exression under the radical (called the discriminant) would have come out to sometihng with a whole number square root. And if we'd started out with sometihng that has a double root, the discriminant would have come out to 0. Try it and see, with some of the other exercises in your homework.
2006-12-31 13:21:44 · answer #1 · answered by Joni DaNerd 6 · 0⤊ 0⤋
This is the equation for finding the roots of a quadratic equation.
ax^2 + bx + c
where a, b, and c are the co-efficients of x
2006-12-31 13:03:57 · answer #2 · answered by ve1luv 2 · 1⤊ 0⤋
This is the quadratic formula.
Suppose you have the equation in the form
ax^2 + bx + c = 0, for constants a, b, and c.
Then, to solve for x, you use the quadratic formula.
x = [-b +/- sqrt(b^2 - 4ac)]/(2a)
The "+/-" indicates that you can potentially get two answers.
2006-12-31 12:56:24 · answer #3 · answered by Puggy 7 · 0⤊ 1⤋
It's the quadratic equation. It's used when a quadratic equation can't be solved by normal means
2007-01-03 23:43:24 · answer #4 · answered by manc1999 3 · 0⤊ 0⤋
this is the quadratic formula to
solve the equation of the form
ax^2+bx+c=0
i hope that this helps
2006-12-31 20:39:41 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Can you be more specific on this question.
2006-12-31 12:57:55 · answer #6 · answered by Anonymous · 0⤊ 0⤋