PS Equation

Shadow · Posted: Tue Jul 10, 2007 9:31 pm Post subject: PS Equation

If (2-v5)x=-1, then x=

A. 2+v5
B. 1+(v5)/2
C. 1-(v5)/2
D. 2-v5
E. -2-v5

Guest · Posted: Tue Jul 10, 2007 10:27 pm Post subject:

is the question : [2-sqrt(5)]x=-1

then the anwser (A)

=> x= -1/[2-sqrt(5)]
=> x = {-1 * [2+sqrt(5)] }/ {[2-sqrt(5)] * [2+sqrt(5)]} ( conjugate multiplication)

=> x = -[2+sqrt(5)]/ [2^2 - sqrt(5)^2]

=> x = -[2+sqrt(5)]/ [4-5]

= x = 2 + sqrt(5)

Shadow · Posted: Tue Jul 10, 2007 10:46 pm Post subject:

Actually this was the way in which the question was presented and i did doubt if v is nothing but sqrt.....i guess it can only be solved if v is assumed as sqrt....