Question 218411
{{{ sqrt( 7x + 44 ) = x}}}
Square both sides
{{{7x + 44 = x^2}}}
{{{x^2 - 7x - 44 = 0}}}
I can solve with quadratic formual
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
{{{a = 1}}}
{{{b = -7}}}
{{{c = -44}}}
{{{x = (-(-7) +- sqrt( (-7)^2-4*1*(-44) ))/(2*1) }}}
{{{x = (7 +- sqrt(49 + 176))/2 }}}
{{{x = (7 +- sqrt(225))/2 }}}
{{{x = (7 +- 15)/2 }}}
{{{x = 11}}}
{{{x = -4}}}
check answers:
{{{ sqrt( 7x + 44 ) = x}}}
{{{ sqrt( 7*11 + 44 ) = 11}}}
{{{ sqrt( 121 ) = 11}}}
{{{11 = 11}}}
and
{{{ sqrt( 7*(-4) + 44 ) = -4}}}
{{{ sqrt( 16 ) = -4}}}
{{{ -4 = -4}}} (one of the square roots is minus)
OK