Rezolvati in R ecuatiile a)2x la puterea 2-3x-2=0 b)x la puterea 2-9x-20=0 c)2x la puterea 2+7x-4=0​

Explicație pas cu pas:

a)2x²-3x-2=0

a = 2 | ∆ = b² - 4ac

b = -3 | ∆ = (-3)² - 4 • 2 • (-2)

c = -2 | ∆ = 9 + 16

∆ = 25 > X1,2=

[tex] \frac{ - b ± \sqrt{∆} }{2a} = \frac{ - ( - 3)± \sqrt{25} }{2 \times 2} = \frac{3±5}{4} [/tex]

X1=

[tex] \frac{3 - 5}{4} = - \frac{1}{2} = - 0,5[/tex]

X2=

[tex] \frac{3 + 5}{4} = \frac{8}{4} = 2[/tex]