Respuesta :
[tex]3x^2 -42x + 9 = -5[/tex]
Subtract 9 from both sides
[tex]3x^2 -42x = -5 - 9[/tex]
[tex]3x^2 -42x = -14[/tex]
Divide by 3 through
[tex]x^2 -14x = - \dfrac{14}{3} [/tex]
Add (b/2)^2 to form perfect square
[tex]x^2 -14x + (\dfrac{14}{2})^2 = - \dfrac{14}{3} + (\dfrac{14}{2})^2 [/tex]
Form perfect square
[tex](x -7)^2 = \dfrac{7}{3}[/tex]
square root both sides
[tex](x -7) = \pm \sqrt{\dfrac{7}{3}} [/tex]
Add 7 to both sides
[tex]x = \pm \sqrt{\dfrac{7}{3}} + 7[/tex]
Rewrite the answer into 2 different answers
[tex]x = 7 + \sqrt{\dfrac{7}{3}} \ or \ 7 - \sqrt{\dfrac{7}{3}}[/tex]
Subtract 9 from both sides
[tex]3x^2 -42x = -5 - 9[/tex]
[tex]3x^2 -42x = -14[/tex]
Divide by 3 through
[tex]x^2 -14x = - \dfrac{14}{3} [/tex]
Add (b/2)^2 to form perfect square
[tex]x^2 -14x + (\dfrac{14}{2})^2 = - \dfrac{14}{3} + (\dfrac{14}{2})^2 [/tex]
Form perfect square
[tex](x -7)^2 = \dfrac{7}{3}[/tex]
square root both sides
[tex](x -7) = \pm \sqrt{\dfrac{7}{3}} [/tex]
Add 7 to both sides
[tex]x = \pm \sqrt{\dfrac{7}{3}} + 7[/tex]
Rewrite the answer into 2 different answers
[tex]x = 7 + \sqrt{\dfrac{7}{3}} \ or \ 7 - \sqrt{\dfrac{7}{3}}[/tex]
