1)2(х-5)=9 2)-(х+8)=3

2(х-5)=9      2*х-2*5=9        2х-10=9            2х=9+10           2х=19     х=19:2       х=9,5           -(х+8)=3          -1*х+-1*8=3            -х+-8=3           -х=3--8               -х=11       х=-11