Larisatopid
a fost răspuns

1) a)
Dacă a/b=2/7, calculati 3a/b .
    b)
Dacă x/y=1/2 si y/z=3/4, calculați x/z si xz/y la puterea doua .

2)
Aflați x din proporția  a) x/4=5/3, b)x/x+1=3/4

Răspuns :

Radusssid
1) a)   [tex] \frac{a}{b}=\frac{2}{7} \\ \frac{3a}{b}=3* \frac{a}{b}=3* \frac{2}{7} = \frac{3*2}{7} = \frac{6}{7}[/tex]

b)  [tex] \frac{x}{y}= \frac{1}{2} => y=2x \\ \frac{y}{z} =\frac{3}{4} => \frac{2x}{z}=\frac{3}{4} =>2* \frac{x}{z} =\frac{3}{4}=> \frac{x}{z} = \frac{ \frac{3}{4} }{2} => \frac{x}{z} = \frac{3}{8}[/tex]

2) a)[tex] \frac{x}{4} = \frac{5}{3} => x =\frac{4*5}{3} => x= \frac{20}{3} => x=6,(6)[/tex]
    b)[tex] \frac{x}{x+1} = \frac{3}{4} => 3(x+1)=4x =>3x+3=4x |-3x =>x=3[/tex]

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