Question

-4 x la patrat +25 = 0

Answer 1

$\it -4x^2+25=0 \Rightarrow 25-4x^2=0 \Rightarrow 5^2-2^2x^2=0 \Rightarrow (5-2x)(5+2x)=0\Rightarrow \\ \\ \Rightarrow \begin{cases}\it 5+2x=0 \Rightarrow 2x=-5 \Rightarrow x=-\dfrac{5}{2}\Rightarrow x_1=-2,5\\ \\ \it 5-2x=0\Rightarrow 5=2x\Rightarrow x=\dfrac{5}{2}\Rightarrow x_2=2,5 \end{cases}$

Answer 2

- 4x² + 25 = 0

25 - 4x² = 0

(5 - 2x)(5 + 2x) = 0

5 - 2x = 0 => 2x = 5 => x₁ = 5/2

5 + 2x = 0 => 2x = - 5 => x₂ = - 5/2