Question 430207
That's right. You just need to solve the square equation.
{{{x^2 + x^2 + 8x + 16 = x^2 + 16x + 64}}}
{{{x^2 - 8x - 48 = 0}}}
{{{D = 8^2 + 4*48 = 256}}}
{{{x = (8 + 16)/2 = 12}}}
Another root is negative.