Răspuns:
B) nr= 21; 22; 23; 24.
C) nr= 82; 84; 86.
D) nr= 13; 14; 15; 16; 17.
Explicație pas cu pas:
La A) nu cred ca ai scria toata cerinta!!
B)nr= x; x+1; x+2; x+3
x+x+1+x+2+x+3=90
4x+6=90
4x=84
x=21
x+1=22
x+2=23
x+3=24
C)nr= x; x+2; x+4
x+x+2+x+4=252
3x+6=252
3x=246
x=82
x+2=84
x+4=86
D)nr= x; x+1; x+2; x+3; x+4
x+x+1+x+2+x+3+x+4=75
5x+10=75
5x=65
x=13
x+1=14
x+2=15
x+3=16
x+4=17