Question

descubra o valor de: A- 4/5 + x/5= 9/5 , B- 7/6 + x/3=9/6, C- 5/8 × X/5= 30/40, D- 2/4 : x/7= 14/20

Answer 1

A- 4/5 + x/5= 9/5

$\frac{4+x=9}{5} =\frac{x=9-4}{5} =x=5$

B- 7/6 + x/3=9/6

$\frac{7}{6} +\frac{x}{3} =\frac{9}{6}$

mmc=6

$\frac{7+2x=9}{6}\\\\ \frac{2x=9-7}{6} \\\\2x=2\\\\x=\frac{2}{2} \\\\x=1$

C- 5/8 × X/5= 30/40

$\frac{5}{8} .\frac{x}{5} =\frac{3}{4} \\ \\ \frac{5x}{40} =\frac{3}{4} \\ \\ 20x=120\\ \\ x=\frac{120}{20} \\ \\ x=6$

D- 2/4 : x/7= 14/20

$\frac{2}{4} :\frac{x}{7} =\frac{2}{4} .\frac{7}{x} =\frac{14}{4x} \\ \\ \frac{14}{4x} =\frac{14}{20} \\ \\ 4x=20\\ \\ x=\frac{20}{4} \\ \\ x=5$