Solve 5x + 7

Question

Solve 5x + 7 < 2 and 5x + 7 ≥ –18.
For equations 1 and 2 i got:
x < –1 , x ≥ –5

Is my answer
x < –1 and x ≥ –5
OR
x < –1 or x ≥ –5
And Why?

smarty · Answer

And what is the difference between the and & the or

smarty · Answer

@zepp

zepp · Answer

Hold on a second :)

smarty · Answer

No worries.

zepp · Answer

The difference between and / or:

AND: A solution set that will work for both of them

OR: The solution set of both equation, mean that you would have 2 solution sets, 1 for the first inequation, second one for the second inequation.

zepp · Answer

So you need to find the value of that satisfies both 5x + 7 < 2 and 5x + 7 ≥ –18 inequalities.

smarty · Answer

So in my case would it be And?

zepp · Answer

You made a mistake on when solving the first equation.

smarty · Answer

I just checked it, and i still got x<-1

zepp · Answer

Um, right, lemme check again.

smarty · Answer

hmk.

zepp · Answer

Okay, they are all correct, sorry.

zepp · Answer

Do you know intersection/union?

smarty · Answer

alright, no i don't know intersection/union...

zepp · Answer

Oh, it's really simple, lemme explain:
I have x>4 and x<7

Let's find the union/intersection of this.
|dw:1340171993058:dw|

Their union would be all real numbers
Their intersection would be from 4 to 7, written as ]4,7[ or 4<x<7