Question

|х|<7; |у|>9; |-х+3|>5
|5+а|<15 помогите пожалуйста

Answer 1

$|x|<7\; \; \to \; \; \; \; -7<x<7\; \; ,\; \; \; x\in (-7,7)\\\\|y|>9\; \; \; \to \; \; \left [ {{y>9} \atop {y<-9}} \right.\; \; \to \; \; y\in (-\infty ,-9)\cup (9,+\infty )\\\\|-x+3|>5\; \; \to \; \; \left [ {{-x+5>5} \atop {-x+5<-5}} \right.\; \; \left [ {{x<0} \atop {x>10}} \right.\; \; x\in (-\infty ,0)\cup (10,+\infty )\\\\|5+a|<15\; \; \to \; \; -15<5+a<15\; ,\; \; -20<a<10\; ,\; \; a\in (-20,10)$

$\star \; \; |x|<a\; \; \Rightarrow \; \; -a<x<a\; \; ,\; \; \; ----(-a)\; //////\; (a)----\\\\\star \; \; |x|>a\; \; \Rightarrow \; \; \left [ {{x>a} \atop {x<-a}} \right.\; \; \; \qquad \; \; ////////\; (-a)---(a)\; ////////$