Question

Resuelve estas ecuaciones de segundo grado : a) x2-9=0 b) x2-1=0 c) 2x2-2=0 d) 3x2-75=0 e) 18-2x2=0 f) 9x2+x=4+x g) x2-5x=9-5x

Answer 1

$x^{2} -9 = 0$
(x+3)(x-3) = 0
x = 3   y x = -3
CS = (-3; 3)


$x^{2} -1 = 0$
(x+1)(x-1) = 0
x = 1   y    x = -1
CS = (-1; 1)



$2 x^{2} -2 = 0$
$2(x^{2} -1) = 0$
$x^{2} -1 = \frac{0}{2}$
$x^{2} -1 = 0$
(x+1)(x-1) = 0
x = 1   y x = -1
CS = (-1; 1)


$3x^{2}-75 = 0$
$3(x^{2}-25)= 0$
$(x^{2}-25)= \frac{0}{3}$
 $(x^{2}-25)= 0$
(x+5)(x-5) = 0
x = 5   y    x = -5
CS = (-5; 5)