12-2.5*(3x-5)=4/5*(3-10x)
12-2.5*(3x-5)=4/5*(3-10x); 12-7,5х+12,5=2,4-8х; -7,5х+8х=2,4-24,5; 0,5х=-22,1; Х=-22,1:0,5; Х=-44,2