Answer:
x = 8,
Step-by-step explanation:
[tex]\displaystyle \frac{4}{x} = \frac{5}{10}[/tex].
[tex]x \ne 0[/tex] for it is a denominator. Multiply both sides with the product of the two denominators: [tex]10\;x[/tex]:
[tex]\displaystyle \frac{4}{x}\cdot (10\; x) = \frac{5}{10}\cdot (10\;x)[/tex].
[tex]40 = 5\; x[/tex].
Multiply both sides by one over the coefficient of x:
[tex]\displaystyle \frac{1}{5} \times 40 = \frac{1}{5}\times 5\; x[/tex].
[tex]x = 8[/tex].
