Question

rezolvati ecuatiile​

Answer 1

Răspuns:

Explicație pas cu pas:

1)

x^2 - 3x = 0

x(x - 3) = 0

x1 = 0

x2 = 3

__________

2)

4x^2 - 16x = 0

x^2 - 4x = 0

x(x - 4) = 0

x1 = 0

x2 = 4

___________

3)

x^2 - 4x + 4 = 0

(x - 2)^2 = 0

x1 = x2 = 2

____________

4)

8x^2 - 14x - 15 = 0

Δ = 196 + 480 = 676

x1 = (14 + 26)/16 = 40/16 = 5/2

x2 = (14 - 26)/16 = -12/16 = -3/4

Answer 2

${x}^{2} = 3x | \div x \\ x = 3$

$4 {x}^{2} = 16x | \div 4x$

$x = 4$

${x}^{2} - 4x + 4 = 0 \\ {(x - 2)}^{2} = 0 \\ x - 2 = 0 \\ x = 2$

${8x}^{2} - 14x - 15 = 0$

$delta = {b}^{2} - 4ac$

$= 196 + 480 = 676 \\ x1.2 = \frac{ - b + - \sqrt{delta} }{2a}$

$\frac{14 + 26}{16} = \frac{40}{16} = \frac{5}{2}$

$\frac{14 - 26}{16} = \frac{ - 12}{16 } = \frac{ - 3}{4}$