Question

Numerele x si y sunt direct proportionale cu numerele 3 si 4. Aflati cele doua numere , stiind ca y=x+14

Answer 1

Salut,

{x;y} dp {3;4}.

x/3 = y/4 = k

x/3 = k → x = 3k.
y/4 = k → y = 4k.

y = x+14
4k = 3k+14
4k-3k = 14
k = 14.

x = 3k → x = 3•14 → x = 42.
y = 4k → y = 4•14 → y = 56.



Succes! :3

Answer 2

[tex]\it y= x+14 \Rightarrow y-x=14\ \ \ \ \ (*) \\\;\\ \\\;\\ \dfrac{x}{3} =\dfrac{y}{4} \Rightarrow\dfrac{y}{4} =\dfrac{x}{3} =\dfrac{y-x}{4-3} \stackrel{(*)}{=} \dfrac{14}{1}=14 [/tex]


[tex]\it \dfrac{y}{4} =14 \Longrightarrow y=4\cdot14 \Longrightarrow y= 56 \\\;\\ \\\;\\ \dfrac{x}{3} =14 \Longrightarrow x=3\cdot14 \Longrightarrow x= 42[/tex]