Question

aflari nr x si y stiind ca x+ y = 72 iar x- y= 18

Answer 1

se aduna cele doua relatii
x+y+x-y=72+18
2x=90
x=90:2=45

Answer 2

x+y=72; x-y=18 => x= y+18;
y+18+y=72; 2y=72-18; 2y= 54: /2; y=27;
x+27=72; x=72-27;
x=45;
45+27=72;
45-27=18.