Răspuns :

Bunicaluiandreiid

[(2x+3)·(x+2)·2=56]÷2    ⇒   (2x+3)·(x+2)=28     28 =4·7   ⇒       x+2 =4    x=2; aceasta solutie   verifica relatia 2x+3 =7      (2·2+3=7)

b)   (x-1)·(y+2)=1·13   ⇒ I.   x-1=1    x=2    y+2= 13   y=11                                                sau                                 II. x-1=13  x=14    y+2=1     y=-1