Question

Valoarile reala ale lui x pentru care 3xla a doua=48 sunt..........Va roggg imi trebuie dau coroana

Answer 1

3x²=48
x²=48:3
x²=16
x=√16
x=±4

Answer 2

$3x^2 = 48|_{:3} \Longrightarrow x^2 =16 \Longrightarrow \sqrt{x^2} =\sqrt{16} \Longrightarrow |x| = 4 \Longrightarrow x = \pm 4$

Deci, ecuatia admite  doua solutii :

$x_1=-4,\ \ \ \ x_2=4$

Verificarea este imediata (!)

II) Alta  metoda:

[tex]3x^2 = 48|_{:3} \Longrightarrow x^2 =16 \Longrightarrow x^2 =4^2 \Longrightarrow x^2 - 4^2 =0 \Longrightarrow \\\;\\ \Longrightarrow (x-4)(x+4) =0 \\\;\\ x+4=0 \Longrightarrow x=-4 \\ x-4=0 \Longrightarrow x=4[/tex]