quadratic equations!!?

0 ⤊

quadratic equations!!?

Write a quadratic equation with solutions 2+i and 2-i

2007-04-09 12:51:43 · 3 answers · asked by kitty 1 in Science & Mathematics ➔ Mathematics

3 answers

i assume i here is complex number, then i^2 = -1
[ x - (2+i) ] [ x - (2-i) ] = 0
(x - 2 - i) (x - 2 + i) = 0
...
x^2 - 4x + 5 = 0

Kevin

2007-04-09 12:55:49 · answer #1 · answered by sk8erboinhl 2 · 0⤊ 0⤋

Remember that A and B are solutions to (x - A)(x - B)=0, so...

(x - (2+i))(x - (2-i)) = 0
x^2 - (2+i)x - (2-i)x + (2+i)(2-i) = 0
x^2 - 2x - ix - 2x + ix + (4 + 2i - 2i - i^2) = 0
x^2 - 4x + (4 - (-1)) = 0
x^2 - 4x + 5 = 0

2007-04-09 19:57:29 · answer #2 · answered by Anonymous · 0⤊ 0⤋

(x-2-i)(x-2+i) =0
x^2 -4x+5 = 0

2007-04-09 19:58:28 · answer #3 · answered by ironduke8159 7 · 0⤊ 0⤋