Find the solution set of the inequality: |2x + 5| + |4x + 7|

Question

Find the solution set of the inequality: |2x + 5| + |4x + 7| < 30
How would you do this kind of problem? I'm not familiar with how to do it when there are two separate absolute values...

anonymous · Answer

u can write |2x + 5|   as2x + 5 or -(2x + 5)
like that   |4x + 7|  as(4x + 7) or -(4x + 7)
so totally there as 4 possibilities

anonymous · Answer

Alright. I'm still a bit confused...would I do them all separately?

experimentx · Answer

plugin into wolfram ... something interesting there

anonymous · Answer

lol...it is a bit interesting...I need to know how to do these without wolfram though...

experimentx · Answer

http://www4d.wolframalpha.com/Calculate/MSP/MSP3101a2d6g2ee8h3ea1i00002hgi79ai05b5a4cc?MSPStoreType=image/gif&s=61&w=208&h=28

anonymous · Answer

Is that really what I do?

experimentx · Answer

i'm not sure .... though this technique seems pretty promising

anonymous · Answer

But all that results in is the removal of the absolute value no?

experimentx · Answer

yep ... take square and see |dw:1344019775207:dw|