Question 17455
Let x be the integer
then:
x + {{{x^2}}} = {{{(x + 1)^2 - 6}}}
so
x + {{{x^2}}} = {{{ (x^2 + 2x + 1) - 6}}}  (if we multiply out {{{(x+1)^2}}})

x + {{{x^2}}} = {{{x^2 + 2x - 5}}}
subtract {{{x^2}}} from both sides
x = 2x - 5
add 5 to both sides
x + 5 = 2x
now subtract x from both sides
5 = x

check
{{{5 + 5^2}}} = 30
{{{(5+1)^2 - 6}}} = 36 - 6 = 30
 hope this helps