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

18*2x=36x, а у вас 32x

Answer 3

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