Question

4. Calcule as raízes das equações a seguir. (2 pontos)
a. −149x^2 = 0

b. 6x^2 − 72 = 0

c. 4x^2 + 120x = 0

d. −2x^2 + 12x = 0

Answer 1

Resposta:

a ) −149x^2 = 0

$\frac{-149^2}{-149}$ = $\frac{0}{-149}$

$x^{2}$= 0

x= 0

b ) 6$x^{2}$ − 72 = 0

6$x^{2}$= 72

$\frac{6^{2} }{6}$= $\frac{72}{6}$

$x^{2}$ = 12

x = $\sqrt{12}$ , x = -

$\sqrt{12}$ = -2$\sqrt{3}$

-$\sqrt{12}$ = -2$\sqrt{3}$

x = 2$\sqrt{3}$ , x = -2

c ) 4x^2 + 120x = 0

x = $\frac{-120 + \sqrt{120^{2} } -4 .4 . 0 }{2 . 4} : 0$

x = $\frac{-120 + \sqrt{120^{2} }- 4 . 4 . 0 }{2.4} : - 30$

x = 0 , x = -30

d ) −2x^2 + 12x = 0

x = $\frac{-12 +\sqrt{12^{2} }-4 (-2)0 }{2(-2)} :0$

x = $\frac{-12 -\sqrt{12^{2} }-4(-2)0 }{2(-2)} :6$

x = 0, x = 6