12×(1 3/4x+5/8)=-6 1/2
(1 3/4x+5/8)= -6 1/2:12 1 3/4x+5/8= -13/2×1/12 7/4x= -13/24-5/8 7/4x= -13/24-15/24 x= -7/6×4/7 x= -2/3