Question

Giair phương trình sau:

1. (x - 3) (x + 4) = (2 - x) (1 - x)

2. \(\frac{2x}{15}\) - \(\frac{15-2x}{10}\) = \(\frac{7}{6}\)

3. \(\frac{x}{15}\) + \(\frac{x+1}{16}\) + \(\frac{x+2}{17}\) + \(\frac{x+3}{18}\) + \(\frac{x+4}{19}\) = 5

4. \(\frac{x+1}{11}\) + \(\frac{2x-5}{15}\) = \(\frac{3x-47}{17}\) - \(\frac{4x-59}{19}\)

5. x² + 9x + 20 = 0

6. x³ + 2x - 3 = 0

Answer 1

5:x^2 +4x +5x + 20 =0

(x^2 + 4x).(5x+20)

x(x+4).5(x+4)

(x+4).(x+5)

[x+5=0 ->x=-5

[x+4=0 ->x=-4