Question

como faco an+2=an+1-an

Answer 1

an + 2 = an + 1 - an
an + 2 = 1
an = 1 - 2
an = -1

Answer 2

An + 2 = an + 1 - an
+2 -1 = an - an - an
+1 = an - 2an
+1 = - 1an