Can u add up?????

Originally posted by rockinlationchess
[b]x2+10x+40x QF=b 2 +or- “square root symbol” b2 - 4ac

I think rockinlationchess did the quadratic formula wrong, but this is what I got. (the real part is positive)

x+y = 10
xy = 40
x = 40 / y
40 / y + y = 10
y^2 + 40 = 10y => y^2 - 10y + 40 = 0
y = ( 10 =- sqrt(10^2 - 4 * 40) ) / 2
y = 5 +- sqrt(60)/2 i = 5 +- sqrt(15) i
x = 10 - (5 +- sqrt(15) i )
x = 5 +- sqrt (15) i

Originally posted by forkedknight
I think rockinlationchess did the quadratic formula wrong, but this is what I got. (the real part is positive)

x+y = 10
xy = 40
x = 40 / y
40 / y + y = 10
y^2 + 40 = 10y => y^2 - 10y + 40 = 0
y = ( 10 =- sqrt(10^2 - 4 * 40) ) / 2
y = 5 +- sqrt(60)/2 i = 5 +- sqrt(15) i
x = 10 - (5 +- sqrt(15) i )
x = 5 +- sqrt (15) i

Which is exactly what I got and posted nearly 3 days ago.