Question

Решить 4,5,6,7. С описанием срочно

Answer 1

$4); ; a); left { {{-2xgeq 8} atop {5x-1<9}} right.; left { {{xleq -4} atop {x<2}} right. ; ; to ; ; xleq -4; ; ;; ; underline {-8in (-infty ,-4, ]; }\\left { {{-5xleq -10} atop {3x+2>5}} right.; left { {{xgeq 2} atop {x>1}} right. ; ; to ; ; xgeq 2; ; ;; ; underline {5in [, 2,+infty ); }\\\5); ; left { {{x+1<9} atop {-2x<6}} right.; left { {{x<8} atop {x>-3}} right. ; ; to ; ; xin (-3,8)\\left { {{x-2>8} atop {-3x<9}} right.; left { {{x>10} atop {x>-3}} right. ; ; to ; ; x>10; ; ;; ; xin (10,+infty )$

$6); ; ybuvaet:; ; xin (-infty ,1, ]\\vozrastaet:; ; xin [, 1,+infty )\\7); ; 6<x<8; ; ,; ; 8<y<10\\-40<-5x<-30qquad qquad ; ; ; qquad  -30<-5y<-40\\8-40<y-5x<10-30qquad qquad 6-30<x-5y<8-40\\-32<y-5x<-20qquad qquad qquad qquad -24<x-5y<-32$