Question

2x la pătrat - 3x-5=0

Answer 1

Răspuns:

Explicație pas cu pas:

2x² - 3x - 5 = 0

Δ = b² - 4ac = 9 - 4×2×(-5) = 9 + 40 = 49

x1 = (-b + √Δ)/2a  = ( 3 + 7)/4 = 10/4 = 2,5

x2 = (-b - √Δ)/2a = (3 - 7)/4 = -4/4 = - 1

x = {-1; 2,5}

Answer 2

$\it 2x^2-3x-5=0 \Rightarrow 2x^2+2x-5x-5=0 \Rightarrow 2x(x+1)-5(x+1)=0\Rightarrow\\ \\ \\ \Rightarrow (x+1)(2x-5)=0 \Rightarrow \begin{cases} \it x+1=0 \Rightarrow x_1=-1\\ \\ \it 2x-5=0 \Rightarrow2x=5 \Rightarrow x_2=\dfrac{5}{2}=2,5\end{cases}$