18*2x+18*8=540
36x+144=540
36x=540-144
36x=396
x=396:36
x=11
2009-3*2x+3*1=1005
2009-6x+3=1005
2009+3-1005=6x
1007=6x
x=1007/6
nu am y
2a+7b+3c=?
a+2b=208 =>a = 208-2b
b+c=209 => c = 209-b
inlocuim b si c in ecuatia noastra cu 3 necunoscute si obtinem una doar in b
2(208-2b) +7b + 3(209-b)=
416-4b +7b+627-3b=
dispare b ???? ceva e gresit in enunt