Respuesta :

Answer: [tex]k= \frac{1+\sqrt{321} }{8} , \frac{1-\sqrt{321} }{8}[/tex]

Step-by-step explanation:

Move all terms to one side.

[tex]4^{2} -20-k=0[/tex]

Use the Quadratic Formula.

[tex]k=\frac{1+\sqrt{321} }{8}[/tex] , [tex]k=\frac{1-\sqrt{321} }{8}[/tex]

Step-by-step explanation:

4k² - 20 = k

4k² - k - 20 = 0

By quadratic formula :

[tex]x = \displaystyle\frac{-b \pm \sqrt{b^2 - 4ac}}{2a}[/tex]

x =( 1 ± √80 ) / 8

x = (1 ± 4√5)/8