Question 19945
straight away, you should have warning bells ringing, since {{{ -6 (x+5)^2=120 }}} can be altered to {{{(x+5)^2=-20}}}.


From this point, we need to take square roots of both sides, to remove the squared term on the left. However, we then have {{{sqrt(-20)}}}, which has no real solution. You then enter into Complex numbers and i am not sure you have done this topic.


Anyway, here goes:


{{{x+5 = sqrt(-20)}}}
{{{x+5 = sqrt(-1*4*5)}}}
{{{x+5 = sqrt(-1)sqrt(4)sqrt(5)}}}
{{{x+5 = i*sqrt(4)sqrt(5)}}}
{{{x+5 = i*2*sqrt(5)}}}
{{{x+5 = 2sqrt(5)i}}}


--> {{{x = 2sqrt(5)i - 5}}}


jon.