Question

Розв'язати систему способом підстановки {х/8+3у/4=2 {х/2-2у/5=4 пожалуйста помогите

Answer 1

$\displaystyle\bf\\\left \{ {{ \frac{x}{8} + \frac{3y}{4} = 2 \: \: | \times 8 } \atop { \frac{x}{2} - \frac{2y}{5} = 4 \: \: | \times 10}} \right. \\ \displaystyle\bf\\\left \{ {{x + 6y = 16 \: \: | \times ( - 5) } \atop {5x - 4y = 40 }} \right. \\ \displaystyle\bf\\ + \left \{ {{ - 5x - 30y = - 80} \atop {5x - 4y = 40 }} \right. \\ \\ - 30y - 4y = - 80 + 40 \\ - 34y = - 40 \\ y = \frac{40}{34} \\ y = \frac{20}{17} \\ y = 1 \frac{3}{17} \\ \\ x + 6 \times \frac{20}{17} = 16 \\ x + \frac{120}{17} = 16 \\ x = 16 - 7 \frac{1}{17} \\ x = 15 \frac{17}{17} - 7 \frac{1}{17} \\ x = 8 \frac{16}{17}$

Ответ: ( 8 16/17 ; 1 3/17 )