Afire burns an oak forest down to bare ground. over the next 150 years, if the climate remains constant, this area will most likely a) remain bare ground b) return to an oak forest c) become a rain forest d) reclaim

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.

: -)

age range would be the answer