Question 1008300


{{{sqrt( 2x + 15) = x + 6}}}...square both sides

{{{(sqrt( 2x + 15))^2 = (x + 6)^2}}}

{{{ 2x + 15 = x^2 + 12x+36}}}

{{{ 0 = x^2 + 12x+36-2x-15}}}

{{{ x^2 + 10x+21=0}}}

{{{ x^2 + 3x+7x+21=0}}}

{{{ (x^2 + 3x)+(7x+21)=0}}}

{{{ x(x + 3)+7(x+3)=0}}}

{{{ (x+3)(x+7) = 0}}}

solutions:

if {{{ (x+3) = 0}}}=>{{{x=-3}}}
if {{{ (x+7) = 0}}}=>{{{x=-7}}}


{{{ graph( 600, 600, -10, 10, -10, 25, x^2 + 10x+21) }}}