1)a*8=408*2 => 8a=816 => a=816/8 => a=102
2)a-b=443 => a=b+443
a/b=5, rest 3 => a=5b+3 => b+443=5b+3 => 4b=440 => b=440/4 => b=110 si a=110+443=553
3) a+b=443 => a=443-b
a/b=3,rest3 => a=3b+3 => 443-b=3b+3 => 4b=440 => b=110 => a=443-110=333
4)notam jumatatea unu br cu a si nr cu 2a
a+2a=645 => 3a=645 => a=215 si nr respectiv este 2*215=430
5)915/a>300 => 915>300a => 915/300 >a => 305/100 >a
816/a<210 => a>816/210 = > a>105/408
100a<420<150a
100a<420 => a<42/10 => a<21/5
420<150a => a > 42/15
42/15<a<42/10
