5x^2+x=4 можно решение

Question

5x^2+x=4
можно решение

Answer 1

5x^2 + x = 4,
5x^2 + x - 4 = 0,

D = b² - 4ac = 1² - 4 × 5 × (-4) = 1 + 4 × 5 × 4 = 1 + 80 = 81, D>0,

"/" - деление

x1 = - B + √D / 2a = -1 + √81 / 2 × 5 = -1 + √81 / 10 = -1 + 9 / 10 = 4 / 5
x2 = - B - √D / 2a = -1 - 9 / 10 = -1.

x1 = 4/5
x2 = -1.

Ответ: 4/5, -1.