Răspuns:
3 + 3 × (3 + 3 × 12) = 9a + 9 + 3
3 + 3 × 39 = 9a + 12
3 + 117 - 12 = 9a
108 = 9a
a = 108 : 9
a = 12
Răspuns: [tex]\green{\underline{~\bf a = 12~}}[/tex]
Explicație pas cu pas:
[tex]\bf 3+3\cdot [3+3\cdot(3+3\cdot3)]=(3\cdot a+3)\cdot3+3[/tex]
[tex]\bf 3+3\cdot [3+3\cdot(3+9)]=9a+9+3[/tex]
[tex]\bf 3+3\cdot (3+3\cdot12)=9a+9+3[/tex]
[tex]\bf 3+3\cdot (3+36)=9a+12[/tex]
[tex]\bf 3+3\cdot 39 =9a+12[/tex]
[tex]\bf 3+117 =9a+12[/tex]
[tex]\bf 120 =9a+12[/tex]
[tex]\bf 120 -12 =9a[/tex]
[tex]\bf 108 =9a[/tex]
[tex]\bf 9a = 108 ~~~\bigg|:9[/tex]
[tex]\green{\underline{~\bf a = 12~}}[/tex]
[tex]==pav38==[/tex]
