Question

решить неравенство
(x+5)^2-(x-13)^2>31x

Answer 1

(x+5-x+13)(x+5+x-13)>31x
18(2x-8)>31x
36x-144>31x
5x>144
x принадлежит (28,8;+бесконечность)

Answer 2

$(x+5)^2-(x-13)^2\ \textgreater \ 31x \\\\ x^2+10x+25-(x^2-26x+169)\ \textgreater \ 31x \\\\ 10x+25+26x-169-31x\ \textgreater \ 0 \\\\ 5x\ \textgreater \ 144 \\\\ x\ \textgreater \ 28.8$