Question

корень из (2X^2-7X-9) минус X=1

Answer 1

√ ( 2x² - 7x - 9) - x = 1
√ ( 2x² - x - 9) = x + 1
2x² - x - 9 = ( x + 1)²
2x² - x - 9 = (x + 1)(x + 1)
2x² - x - 9 = x² + x + x + 1
2x² - x - 9 = x² + 2x + 1
2x² - x - 9 - x² - 2x - 1 = 0
x² - 3x - 10 = 0
D = b² - 4ac = 9 - 4 × 1 × ( - 10 ) = 9 + 40 = 49 = 7²
x₁ = 3 + 7 / 2 = 5
x₂ = 3 - 7 / 2 = - 4 / 2 = - 2

Ответ: x₁ = 5, x₂ = - 2

Answer 2

перерешаю: 2x^2 - 7x - 9 = x^2 + 2x + 1

Answer 3

2x^2 - 7x - 9 - x^2 - 2x - 1 = 0 x^2 - 9x - 10 = 0

Answer 4

D = 81 - 4 * ( - 10) = 81 + 40 = 121 x1 = 9 + 11/2 = 10, x2 = 9 - 11/2 = - 2/2 = -1

Answer 5

значит,ответ: x1 = 10, x2 = - 1

Answer 6

вот теперь сошлось)