Помогите с решением |2-4х|<7

[latex]| 2-4x| extless 7 [/latex][latex] left { {{2-4x extless 7} atop {2-4x extgreater -7}} ight. [/latex][latex] left { {{-4x extless 7-2} atop {-4x extgreater -7-2}} ight. [/latex][latex] left { {{-4x extless 5} atop {-4x extgreater -9}} ight. [/latex][latex]left { {{x extgreater -1.25} atop {x extless 2.25}} ight. [/latex]Ответ: [latex](-1.25;2.25)[/latex][latex]|f(x)| extless a[/latex]  ⇔ [latex] left { {{f(x) extless a} atop {f(x) extgreater -a}} ight. [/latex]