Question

допоможіть будь ласка!!!

Answer 1

Ответ:

$\frac{42}{x(x + 5)} - \frac{3}{x(x - 5) } = \frac{7}{x} \\ 42(x - 5) - 3(x + 5) = 7(x - 5)(x + 5) \\ 42x - 210 - 3x - 15 = 7( {x}^{2} - 25) \\ 39x - 225 = 7 {x}^{2} - 175 \\ 39x - 225 - 7 {x}^{2} + 175 = 0 \\ - 7 {x}^{2} + 39x - 50 = 0 \times ( - 1) \\ 7 {x}^{2} - 39x + 50 = 0 \\ d = {( - 39)}^{2} - 4 \times 7 \times 50 = 1521 - 1400 = 121 = {11}^{2} \\ x1 = \frac{39 + 11}{14} = 3 \frac{8}{14} = 3 \frac{4}{7}$

$x2 = \frac{39 - 11}{14} = \frac{28}{14} = 2$