Question 443162
{{{a + 2 <=-13}}}......... (the "<=" means less and equal to)

{{{a + 2-2 <=-13-2}}}

{{{a + cross(2)-cross(2)<=-15}}}

{{{a <=-15}}}

{{{ graph(500, 500, -20, 10, -20, 10, x<=-15) }}}

interval:

({{{-infinity}}},{{{15}}}]