Question

--2x²-3x-1=0
-X²-5x-6=0
- -x +5x-6=0
- x²+2x-15=0​ . Va rog mult sa ma ajutati. Va multumesc

Answer 1

Răspuns:

-2x²-3x-1=0

-X²-5x-6=0

-x +5x-6=0

-x²+2x-15=0​

Explicație pas cu pas:

-2x²-3x-1=0

Δ = $b^{2} - 4*a*c$ = 9-8 = 1

$x_{1} = \frac{-b + \sqrt{delta}}{2a}$ = $\frac{3+1}{-4}$ = -1

$x_{2} = \frac{-b - \sqrt{delta}}{2a}$ = $\frac{3-1}{-4}$ = $-\frac{1}{2}$

-X²-5x-6=0/(-1)* ⇒X²+5x+6=0

Δ = $b^{2} - 4*a*c$ = 25-24 = 1

$x_{1} = \frac{-b + \sqrt{delta}}{2a}$ = $\frac{-5+1}{2}$ = -2

$x_{2} = \frac{-b - \sqrt{delta}}{2a}$ = $\frac{-5-1}{2}$ = -3

-x +5x-6=0 ⇒4x-6=0 ⇒ 4x=6 ⇒ $x=\frac{6}{4} =\frac{3}{2}$

-x²+2x-15=0/*(-1) ⇒x²-2x+15=0

Δ = $b^{2} - 4*a*c$ = 4-60 = -56 ⇒ Δ < 0 ⇒ $x_{1} ; x_{2}$ ∉ R