Question

If one root of a quadratic equation is 2 - i , what is the equation?

Answer 1

other root = 2+i

Answer 2

(x-(2-i))(x-(2+i))
can u solve further >?

Answer 3

How do we know that's the other root?

Answer 4

COMPLEX ROOTS ALWAYS OCCUR IN PAIRS
if a+ib is one root, a-ib is other root

Answer 5

Okay I'm remembering that now! But how do we formulate the equation?

Answer 6

if a is the root, x-a is the factor

Answer 7

Can you explain further please

Answer 8

since 2-i is a root, x-(2-i) is a factor
since 2+i is a root, x-(2+i) is a factor
since its a quadratic equation, it only has 2 factors which are
(x-(2-i))(x-(2+i))
now just multiply them out

Answer 9

or use (a-b)(a+b) = a^2-b^2

Answer 10

[(x-2) + i ][(x-2)-i] = (x-2)^2 - i^2
getting this ?

Answer 11

I'm piecing it together give me a sec

Answer 12

I got x^2 - 4x + 5 = 0! Wow that's amazing! Thank you so much! Explains it much better than Dr. Chung's book

Answer 13

lol, welcome ^_^