If ax*x + bx + c = 0, then what is x?

Question

anonymous · Answer

ax² + bx + c = 0 is a quadratic equation and it can be solved using the quadratic formula

anonymous · Answer

$$x=\frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }$$

mmd998 · Answer

huh ?

anonymous · Answer

It's a formula you can use to solve quadratic equations (the ones where you have x²).

For example, 
2x² - x - 3 = 0

a would be 2, since it's with x².
b is -1, since it's with x
c is -3, since it's the constant.

So to solve for x, you'd plug them into the formula
$$x=\frac{ -(-1)\pm \sqrt{(-1)^2-4(2)(-3)} }{ 2(2) }$$
$$x=\frac{ 1 \pm \sqrt{25}}{ 4 }$$
$$x=\frac{ 1\pm5 }{ 4 }$$
from here you have two solutions for x
$$x=\frac{ 1+5 }{ 4 }=\frac{6}{4}=\frac{3}{2}$$
$$x=\frac{ 1-5 }{ 4 }=\frac{ -4 }{ 4 }=-1$$