Park, CKim, SOAlaca, C2024-07-182024-07-182008-1901http://akademikarsiv.cbu.edu.tr:4000/handle/123456789/6969INT SCIENTIFIC RESEARCH PUBLICATIONSArticleLet M(1)f (x, y) : = 3/4 f (x + y) -1/4 f (-x -y) + 1/4 f (x - y) + 1/4 f(y - x) -f (x) -f (y), M(2)f(x, y) : = 2f( x + y/2) + f ( x - y/2 ) + f ( y - x/2 ) -f (x) -f (y). We solve the additive-quadratic rho-functional equations M(1)f (x, y) = rho M(2)f(x, y), (1) and M(2)f(x, y) = rho M(1)f (x, y), (2) where rho is a fixed nonzero number with rho not equal 1. Using the fixed point method, we prove the Hyers-Ulam stability of the additive-quadratic rho-functional equations (1) and (2) in Banach spaces. (C)2017 All rights reserved.