How do you solve (2x-1)/(x+5)>=02x1x+50 using a sign chart?

1 Answer
Dec 19, 2016

The answer is x in ] -oo,-5 [ uu [1/2, +oo[x],5[[12,+[

Explanation:

Let f(x)=(2x-1)/(x+5)f(x)=2x1x+5

Let's do the sign chart

color(white)(aaaa)aaaaxxcolor(white)(aaaa)aaaa-oocolor(white)(aaaa)aaaacolor(white)(aaaa)aaaa-55color(white)(aaaa)aaaacolor(white)(aaaa)aaaa1/212color(white)(aaaa)aaaa+oo+

color(white)(aaaa)aaaax+5x+5color(white)(aaaaaa)aaaaaa-color(white)(aa)aacolor(white)(aaa)aaacolor(white)(aaaa)aaaa++color(white)(aaa)aaa#color(white)(aa)+#

color(white)(aaaa)aaaa2x-12x1color(white)(aaaaaa)aaaaaa-color(white)(aa)aacolor(white)(aa)aacolor(white)(aaaa)aaaa-color(white)(aaa)aaa#color(white)(aa)+#

color(white)(aaaa)aaaaf(x)f(x)color(white)(aaaaaaaa)aaaaaaaa++color(white)(aa)aacolor(white)(aa)aacolor(white)(aaaa)aaaa-color(white)(aaa)aaa#color(white)(aa)+#

Therefore,

f(x)>=0f(x)0, when x in ] -oo,-5 [ uu [1/2, +oo[x],5[[12,+[

graph{y-(2x-1)/(x+5)=0 [-52, 52.07, -26, 26]}