x = (-5 +/-�ã85)/10

do you mean -0.5 or -5

is this right?

solve by using the quadratic formula:
5x^2+5x=3

i get:

x= -0.5 (+/-)((sqrt(85)/(5))

check up on your proper use of the formula

I got x = (-5 +/-√85)/10

which, if you want to separate it into two terms is

1/2 +/- √85/10 (you had /5)

some of your teachers might consider it "bad form" to give an answer partially in decimals and partially in fractions
Choose either one or the other.