[tex]10 x( \frac{1}{2} + \frac{1}{4} ) = 5x \times \frac{1}{2} \\ 5x + 2.5x = 5x \times \frac{1}{2} | \times 2 \\ 10x + 5x = 10x \times 1 | \div 10x \\ \frac{10x + 5x}{10x} = 1 \\ \frac{15x}{10x} = 1 \\ 1.5x = 1 \\ x = \frac{1}{1.5} = \frac{10}{15} = \frac{2}{3} [/tex]
Myślę że pomogłem ;)
