Question

Determine o valor de x nas proporções
a)8\32=2\x
b)5\3=x\21
c)7\x=3\27
d)x\x+1=1\2
e)5\x=4\x+1
f)x\9=x-2\15

Answer 1

Resposta:

a)8\32=2\x

$\frac{8}{32} = \frac{2}{x} \\ \\ 8x = 64 \div (8) \\ x = 8$

b)5\3=x\21

$\frac{5}{3} = \frac{x}{21} \\ \\ 3x =105 \div (3) \\ x = 35$

c)7\x=3\27

$\frac{7}{x} = \frac{3}{27} \\ \\ 3x = 189 \div (3) \\ x = 63$

d)x\x+1=1\2

$\frac{x}{x + 1} = \frac{1}{2} \\ \\ 2x = x + 1 \\ 2x - x - 1 = 0 \\ x - 1 = 0 \\ x = 1$

e)5\x=4\x+1

$\frac{5}{x} = \frac{4}{x + 1} \\ \\ 4x = 5 \times (x + 1) \\ 4x = 5x + 5 \\ 4x - 5x - 5 = 0 \\ - x - 5 = 0 \\ - x = 5 \times ( - 1) \\ x = - 5$

f)x\9=x-2\15

$\frac{x}{9} = \frac{x - 2}{15} \\ \\ 15x = 9 \times (x - 2) \\ 15x = 9x - 18 \\ 15x - 9x + 18 = 0 \\ 6x + 18 = 0 \\ 6x = - 18 \\ \\ x = - \frac{18}{6} \\ \\ x = - 3$