As shown in the question, the following equation can be extracted:

An apple = an orange+a berry.

An apple+an orange =9 berries.

Simplify:

An orange = an apple-a berry (simplified by the first formula)

An orange =9 berries-an apple (simplified by the second formula)

Add the two formulas to get: two oranges =8 berries.

Then: an orange =4 berries.