Question

why are there so many different methods to solve quadratic equations???

Answer 1

Quadratic equations are some of the easiest equations to work with.

Answer 2

what method do you use?

Answer 3

Completing the square

Answer 4

x^2-3x=0 could you solve that for me please?

Answer 5

By completing the square:

1. Divide both sides by a^-1
2. Add -c to both sides
3. Add (b^2)/4 to both sides
4. Factor the left side as a perfect square
5. Take the square root of both sides
6. Solve for x and you're done.

a := 1
b := -3
c := 0

1. x^2 - 3x = 0 (no operation performed)
2. x^2 - 3x = 0 (no operation performed)
3. x^2 - 3x + 9/4 = 9/4 (added b^2/4 to both sides)
4. (x - 3/2)^2 = 9/4 (factored the left side)
5. \[x - \frac{3}{2} = \pm \frac{3}{2}\]
6. \[x = 0 \ \ \ or \ \ \ x = 3\]

Answer 6

most people would see that x = 0 or x = 3 right away though :-P I just wanted to illustrate the method of completing the square

Answer 7

oops step 1 should be multiply by a^-1 (or divide by a :-P )

Answer 8

I already knew the answer, i am just trying to get my head around completing the square and quadratic formula.

Answer 9

the quadratic formula: \[x = \frac{-b \pm\sqrt{\Delta}}{2a}\]where \[\Delta = b^2 - 4(a*c)\]

Answer 10

u can use quadratic formula or use completing the sqaure method

Answer 11

or trial and error

first find the common factor

then find

what two numbers add to give you b

and what two numbers multiply to give you c

put in two separate brackets with the common factor and the two numbers you found each in seperate brackets

(x + 0) (x - 3) = 0

to check just expand

x^2 - 3x + 0 = 0

so your answers would be

x + 0 = 0

x - 3 = 0

x = 0

x = 3