I will give 5 stars, thanks, and Branliest if there are two answers!! How is the streak color of a mineral best tested?

a mineral is scraped or rubbed hardly on sandpaper or unglazed porcelain

( please mark me as brainliest that would be most appreiciated )

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.

: -)