Question

stiind ca a supra b=4 unde a si b sunt numere reale naturale arătați ca 3a-2b supra b=10

Answer 1

a/b=4 => a=4b;
(3a-2b)/b  = (3*4b -2b)/b= (12-2)b/b = 10b/b =10

Answer 2

[tex]\it \dfrac{a}{b} = 4 \Rightarrow a=4b|_{\cdot3} \Rightarrow 3a = 12b\ \ \ \ (*) \\\;\\ \\\;\\ \dfrac{3a-2b}{b}\ \stackrel{(*)}{=}\ \dfrac{12b-2b}{b}=\dfrac{10b}{b}=10[/tex]