Which form of virus did sabin use for the vaccine?

The most appropriated answer would be attenuated poliovirus.

Sabin developed the first oral polio vaccine in which he used the attenuated or inactivated form of poliovirus (IPV).

His vaccine contained an attenuated form of all the three strains of the poliovirus.

The vaccine was commercialized in 1961

Might be really late but its INACTIVATED on Edge. hoped this helped for others. :)

Explanation:

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)