Question

Solve the compound inequality 60 < 20u < 120.
Question 1 options:
1)
3 < u < 6
2)
6 > u > 7
3)
6 < u < 3
4)
3 > u < 6

Answer 1

60 <20 u <120

simply divide BOTH sides by 20. what do you get?

Answer 2

6 ?

Answer 3

there must be TWO sides

Answer 4

sort of think of having a equal sign on both sides, so what ever you do to one part you do to all three parts, the only thing you have to do it flip the signes when you devide or multiply by a negative

Answer 5

what's 60/20?

Answer 6

3

Answer 7

here's an easy example so you have an idea

9 < 3x < 12

divide both sides by 3

3 < x < 4

do you get it?

Answer 8

i think it's not "both" sides since there are three sides heh

Answer 9

:)

Answer 10

OKAY I do . its just the signs that confuses me

Answer 11

hmm well in this case there's no sign change since there's no division of negative so you're safe :)

Answer 12

only flip them when you deal with negatives
example
20<-2x<10 since we devide away the -2 we flip the signs
-10>x>-5

Answer 13

here's an example of sign change

9 < -3x < 12

divide all sides by -3

-3> x > -4

Answer 14

ooo wow that's easy. im always over thinking when it comes to algebra

Answer 15

thank you guys

Answer 16

there's always room for mistakes ^_^

Answer 17

what about this proble. is it the same thing

Solve the compound inequality 9 + 3n alt= 3 or 5n < 30

Answer 18

alt?

Answer 19

maybe rewrite that

Answer 20

okay nevermind. you know the sign that has > and it has a minus sign underneath

Answer 21

thats an equals sign just write it like <= or >= if you want

Answer 22

okay ill do that Solve the compound inequality 9 + 3n >= 3 or 5n < 30

Answer 23

remind me...is solving compound inequality any different from solving inequalities individually?