Question 734375
solve the equation: x - 2 sqrt of x = 8
.
{{{x - 2sqrt(x) = 8 }}}
This is a "quadratic".
Let {{{y = sqrt(x)}}}
then we can rewrite the equation as:
{{{y^2 - 2y = 8}}}
{{{y^2 - 2y - 8 = 0}}}
{{{(y+2)(y-4) = 0}}}
y = {-2,4}
.
but, we needed x so:
{{{-2 = sqrt(x)}}}
{{{4 = x}}}
and
{{{4 = sqrt(x)}}}
{{{16 = x}}}