Răspuns
1)
D:5=c si r unde c=r+10
r<5 => r={1;2;3;4} => c={11;12;13;14}
D:5=11 r 1 => D=5*11+1 => D=55+1 =>D=56
D:5=12 r 2 => D=5*12+2 => D=60+2 => D=62
D:5=13 r 3 => D=5*13+3 => D=65+3 => D=68
D:5=14 r 4 => D=5*14+4 => D=70+4 => D=74
=> numerele care indeplinesc conditia sunt : 56;62;68 si 74
D:3=c si r unde c=r²
r<3 => r={1 ;2} => c={1²;2²} => c={1 ;4}
D:3=1 r 1 => D=3*1+1 => D=3+1 => D=4
D:3=4 r 2 => D=3*4+2 => D=12+2 => D=14
=> numerele care indeplinesc conditia sunt: 4 si 14
2)
m+t+f=80 ani
t=3f
t=m+4 => m=t-4 => m=3f-4
inlocuim in relatie:
3f-4+3f+f=80 ani
7f-4=80
7f=80+4
7f=84
f=84:7
f=12 ani are fiul
t=12*3
t=36 ani are tatal
m=36-4
m=32 ani are mama
verificare:
32+36+12=80 ani au impreuna
3)
a+b+c=214
b>a cu 4 => b=a+4
c>a de 4 ori => c=4a
inlocuim in relatie:
a+a+4+4a=214
6a+4=214
6a=214-4
6a=210
a=210:6
a=35 => b=35+4 => b=39
c=35*4 => c=140
verificare:
35+39+140=214 in total
