Question

1) resolva as seguintes proporções:a) x/5=21/35b)3/4/1/5 =90/xc)9/13=x/26 d)1/7=x-6/49e)2x 1/10=-21/30f)3x 2/x 3=-40/25g)0,3/x=-6/9h)0,2/5=x/200

Answer 1

$a) \frac{x}{5}= \frac{21}{35} \\ \frac{35}{5}=7 \\ \frac{21}{x}=7 \\ \frac{21}{3}=7 \\ x=3$

$b)\frac{ \frac{3}{4} }{ \frac{1}{5} } = \frac{90}{x} \\ \frac{3}{4}. \frac{5}{1}= \frac{90}{x} \\ \frac{15}{4}= \frac{90}{x} \\ \frac{90}{15}=6 \\ \frac{x}{4} =6 \\ \frac{24}{4}=6 \\ x=24$

$c) \frac{9}{13}= \frac{x}{26} \\ \frac{26}{13}=2 \\ \frac{x}{9}=2 \\ \frac{18}{9}=2 \\ x=18$

$d) \frac{1}{7}= \frac{x-6}{49} \\ \frac{49}{7}=7 \\ \frac{x-6}{7}=7 \\ \frac{x-6=49}{7}=7 \\ \frac{55-6}{7}=7 \\ x = 55$

$e) 2x. \frac{1}{10} = \frac{-21}{30} \\ \frac{2x}{10} = \frac{-21}{30} \\ \frac{x}{5}= \frac{-21}{30} \\ \frac{30}{5} = 6 \\ \frac{-21}{x}=6 \\ \frac{-21}{-126}=6 \\ x=-126$

f) não entendi... é 3x.2/3x?? ou 3x.(2/x) .3