1/2×(4-3 1/2x)=1 1/4x-1/21/2*(4-7/2х)=1 1/4х-1/22-7х=1 1/4х-1/2-7х-1 1/4х=-1/2-2-6 4/4х-1 1/4х=-1/2-1 2/2-5 3/4х=-1 3/25 3/4х=2 1/2х=5/2 : 23/4=5/2*4/23х=10/23