How do you solve #2/(x+5)>4/(x+5)+3#?

2 Answers
Jul 30, 2017

#x<-17/3# or #x<-5 2/3#

Explanation:

#2/(x+5)>4/(x+5)+3#

Multiply every term by #(x+5)#.

#(x+5)xx2/(x+5)>(x+5)xx4/(x+5)+3(x+5)#

#cancel((x+5))xx2/cancel(x+5)>cancel((x+5))xx4/cancel(x+5)+3x+15#

#2>4+3x+15#

#2>3x+19#

Subtract #19# from each side.

#2-19>3x#

#-17>3x#

Divide both sides by #3#.

#-17/3>(3x)/3#

#-17/3>(cancel3x)/cancel3#

#-17/3>x# or #x<-17/3#

Jul 30, 2017

The solution is #x in (-17/3, -5)#

Explanation:

You cannot do crossing over

#2/(x+5)>4/(x+5)+3#

Let's perform some simplifications

#2/(x+5)-4/(x+5)-3>0#

#(2-4-3(x+5))/(x+5)>0#

#(2-4-3x-15)/(x+5)>0#

#(-3x-17)/(x+5)>0#

Let #f(x)=(-3x-17)/(x+5)#

Let's build the sign chart

#color(white)(aaaa)##x##color(white)(aaaaaaa)##-oo##color(white)(aaaaaa)##-17/3##color(white)(aaaaaaa)##-5##color(white)(aaaaaaa)##+oo#

#color(white)(aaaa)##-3x-17##color(white)(aaaaaa)##+##color(white)(aaaaaaa)##-##color(white)(aaaa)##||##color(white)(aaa)##-#

#color(white)(aaaa)##x+5##color(white)(aaaaaaaaaa)##-##color(white)(aaaaaaa)##-##color(white)(aaaa)##||##color(white)(aaa)##+#

#color(white)(aaaa)##f(x)##color(white)(aaaaaaaaaaa)##-##color(white)(aaaaaaa)##+##color(white)(aaaa)##||##color(white)(aaa)##-#

Therefore,

#f(x)>0# when #x in (-17/3, -5)#

graph{2/(x+5)-4/(x+5)-3 [-24.25, 11.8, -10.45, 7.57]}