Question

Malik is solving the equation x^2- 10x - 11 = 0 using the complete the square method.

Answer 1

Answer:

In line 4, he did the mistake. He should have square rooted the other side as changing sides changes square to square root.

explanation:

line 1:   $\sf p^2 - 10p - 11 = 0$

$\sf p^2 - 10p = 11$

line 2:   $\sf p^2 - 10p + 25 = 11 + 25$

$\sf p^2 - 5p -5p+ 25 = 36$

$\sf p(p-5)-5(p-5) = 36$

line 3:   $\sf (p-5)^2 = 36$

line 4:   $\sf p - 5 = \pm \sqrt{36}$

$\sf p-5 = 6$   or   $\sf p-5 = -6$

line 5: $\sf p = 11$  or   $\sf p = -1$

line 6: The solution is p = 11 or p = -1