Question

решите уравнение x-20/x=1

Answer 1

x/20 - x = 1 / x
x² = 20 - x
x² + x - 20 = 0
D = b² - 4ac = 1² - 4 × 1 × ( - 20) = 1+ 80 = 81 =9²
x₁ = - 1 +9 / 2 = 4
x₂ = - 1 - 9 / 2 = - 5