Vector OC= vector OA+ vector AC= vector OA+3 vector AE=-2 vector OA+3 vector OA+3 vector AE=3 vector OE-2 vector OA.

Vector OC= vector OB+ vector BC= vector OB+3 vector BF=-2 vector OB+3 vector BF=3 vector OF-2 vector OB.

Two formulas are added: 2 vector OC=3 vector OE+3 vector OF-2 (vector OA+ vector OB)=3 vector OE+3 vector OF-2 vector OC.

∴ vector OC=3/4 vector OE+3/4 vector OF

So: λ+μ=3/4+3/4=3/2.