Răspuns :
Răspuns: a = 12 -> numarul
Explicație pas cu pas:
( a - 10 ) × 2 = a / 3 [ × 3
3 × ( a - 10 ) × 2 = a
6 × a - 60 = a
6 × a - a = 60
5 × a = 60
a = 60 : 5
a = 12 ∈ R
Verific:
( 12 - 10 ) × 2 = 12 : 3
2 × 2 = 4 √
[tex]\it\ Vom\ nota\ num\breve{a}rul\ cerut\ cu\ \ x.\\ \\ (x-10)\cdot2=x:3\ \Rightarrow 2x-20=x:3|_{\cdot3} \Rightarrow 6x-60=x \Rightarrow 6x-x=60 \Rightarrow \\ \\ \Rightarrow 5x=60 \Rightarrow x=\dfrac{60}{5} \Rightarrow x=12[/tex]