Question

URGENTE PLMDDS
dou 5 estrelas​

Answer 1

Resposta:

1) A) $x=3$

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2) A) $x=5$

B) $x=3$

C) $x=1$

D) $x=2$

Explicação passo a passo:

1 ) $\frac{x}{5}=\frac{21}{35}$

$\mathrm{Eliminar\:o\:fator\:comum:}\:7$

$\frac{x}{5}=\frac{3}{5}$

$\mathrm{Multiplicar\:ambos\:os\:lados\:por\:}5$

$\frac{5x}{5}=\frac{3\cdot \:5}{5}$

Simplificar:

$x=3$

2 ) A) $\frac{x+7}{4}=\frac{11-x}{2}$

$\left(x+7\right)\cdot \:2=4\left(11-x\right)$

$2x+14=44-4x$

$2x+14-14=44-4x-14$

$2x=-4x+30$

$2x+4x=-4x+30+4x$

$6x=30$

$\frac{6x}{6}=\frac{30}{6}$

$x=5$

B) $\frac{x+3}{12-x}=\frac{2}{3}$

$\left(x+3\right)\cdot \:3=\left(12-x\right)\cdot \:2$

$3x+9=24-2x$

$3x+9-9=24-2x-9$

$3x=-2x+15$

$3x+2x=-2x+15+2x$

$5x=15$

$\frac{5x}{5}=\frac{15}{5}$

$x=3$

C) $\frac{18}{8+x}=\frac{2}{x}$

$18x=\left(8+x\right)\cdot \:2$

$18x=16+2x$

$18x-2x=16+2x-2x$

$16x=16$

$\frac{16x}{16}=\frac{16}{16}$

$x=1$

D) $\frac{2-2x}{3x}=-\frac{1}{3}$

$\left(2-2x\right)\cdot \:3=-3x\cdot \:1$

$\left(2-2x\right)\cdot \:3=-3x$

$6-6x=-3x$

$6-6x-6=-3x-6$

$-6x=-3x-6$

$-6x+3x=-3x-6+3x$

$-3x=-6$

$\frac{-3x}{-3}=\frac{-6}{-3}$

$x=2$

Espero ter ajudado!! :)