Question

1 Решите уравнение 2х2 – 7х + 5 = 0

Answer 1

Ответ:

$x1 = 2,5.$

$x2 = 1.$

Объяснение:

$2x^2 -7x + 5 = 0$

$a = 2; b = -7; c = 5.$

$D = b^2 - 4ac = (-7)^2 - 4*2*5 = 49 - 40 = 9.$

$x1,2 = \frac{-b ^+- \sqrt{D} }{2a}$

$x1 = \frac{-(-7) + \sqrt{9} }{2*2} = \frac{7+3}{4} = \frac{10}{4} = 2,5.$

$x2 = \frac{-(-7)-\sqrt{9} }{2*2 } = \frac{7-3}{4} = \frac{4}{4} = 1.$