1) 3-4,9z=-5,4-2,8z2,8z-4,9z=-5,4-3-2,1z=-8,4z=-8,4:(-2,1)z=4Проверка3-4,9*4=-5,4-2,8*43-19,6=-5,4-11,2-16,6=-16,62) 5,2х+9=3,4х5,2х-3,4х=-91,8х=-9х=-9:1,8х=-5Проверка 5,2*(-5)+9=3,4*(-5)-26+9=-17-17=-173)0,9у-41=0,5у-50,9у-0,5у=41-50,4у=36У=36:0,4у=90Проверка0,9*90-41=0,5*90-581-41=45-540=40