3x-1=2(x-2)3(x+5)=x-319(y+9)=3(x-8)

а в 3-ем точно y?

3x-1=2x-43x-2x=-4+1x=-3----------3x+15=7-5x3x+5x=7-158x=-8x=-1------------19y-171=3y+2119y-3y=21+17116y=192y=192:16y=12-----------4x-36=3x-244x-3x=-24+36x=12----------6x-27=5x-206x-5x=-20+27x=7------------21-14x=15-15x-14x+15x=15-21x=-6

1) 3х-1=2(х-2)
3х-1=2х-4
3х-2х=-4+1
х=-3
2) 3(х+5)=х-3
3х+15=х-3
3х-х=-3+15
2х=12
х=6
3) 19(х+9)=3(х-8)
19х+171=3х-24
19х-3х=-24-171
16х=-195
х=-12