arbyj
  • arbyj
i need help solving this equation: 18-|9x+2|=-7 i already eliminated 18 and was left with |9x+2| =-25 helper will get a medal!
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
katieb
  • katieb
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
mathmale
  • mathmale
No medal required or needed. Better check the arith. that y ou've done so far. Are you sure that 25 is negative?
mathmale
  • mathmale
Why not try adding 7 to both sides of the equation first?
anonymous
  • anonymous
x=-3

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

arbyj
  • arbyj
i got rid of the 18 bc i have to isolate the absolute value
mathmale
  • mathmale
But if you do add 7 to both sides of the equation, your 18 becomes 25, right? What next?
mathmale
  • mathmale
You'll need to isolate the absolute value expression, as you said.
arbyj
  • arbyj
i did it like this|dw:1449206463340:dw|
mathmale
  • mathmale
Still have a problem with algebraic signs here. Check again.
arbyj
  • arbyj
oh is it the negative sign im leaving?
whpalmer4
  • whpalmer4
Hint: \[-|9x+2| +18=-7\]
mathmale
  • mathmale
There should be no negative sign on either side. Check out whpaler4's input for another view.
whpalmer4
  • whpalmer4
first rule of intelligent tinkering, and algebra: keep all the pieces! :-)
mathmale
  • mathmale
I gravitate to keeping quantities positive whenever I can. What arithmetic operations will both reduce your equation and result in every term being positive?
arbyj
  • arbyj
division?
mathmale
  • mathmale
See whpalmer's equation. What say you change all of the neg signs to pos and all of the pos signs to neg?
arbyj
  • arbyj
okay so i did it in the way whpalmer arranged it. is this correct or am i still missing something? |dw:1449207039696:dw|
mathmale
  • mathmale
|dw:1449207241063:dw|
arbyj
  • arbyj
ohhh okay, that's what i thought at first :P
mathmale
  • mathmale
Here's what I'd do: Given: \[-|9x+2| +18=-7\]
mathmale
  • mathmale
Negate every term. We'll then have:\[-(-|9x+2| +18=-7).or.|9x+2| -18=7,\right?\]
arbyj
  • arbyj
yes
mathmale
  • mathmale
How would you now simplify |9x+2|-18=7?
mathmale
  • mathmale
Hint: If equals are added to equals, the sums are equal.
arbyj
  • arbyj
|dw:1449207458298:dw|
mathmale
  • mathmale
Cool. Just too cool.
mathmale
  • mathmale
Now, that equation breaks down into TWO separate equalities.
arbyj
  • arbyj
yeah 9x+2+25 9x+2=-25
mathmale
  • mathmale
9x+2=25 AND -(9x+2)=25. Seen this kind of action before, when working with absolute value quantities?
arbyj
  • arbyj
*=
mathmale
  • mathmale
How would you solve the first one?
arbyj
  • arbyj
yes
mathmale
  • mathmale
9x+2=25
arbyj
  • arbyj
subtract 2 from both sides
mathmale
  • mathmale
You bet!
mathmale
  • mathmale
Unfortunately, the resulting equation isn't pretty. :(
mathmale
  • mathmale
x = ?
arbyj
  • arbyj
yeah :/ i got x=23/9 and x=-3 for the 2nd equation
mathmale
  • mathmale
Challenge: Check your x=-3 by substition into |9x+2|-7+18
mathmale
  • mathmale
Excuse me: substituion into |9x+2|-7=18
arbyj
  • arbyj
it was correct :)
whpalmer4
  • whpalmer4
I wrote the equation as I did only to make it clear that the "-" in front of the absolute value expression was being inadvertently lost.
whpalmer4
  • whpalmer4
Or perhaps I should say "in the hopes of making it clear" as it didn't do the trick :-)
mathmale
  • mathmale
Cool, I think, to explore various possibilities along the way to efficient problem solving!
arbyj
  • arbyj
thank you so much :)
mathmale
  • mathmale
Satisfied, arby-j?
mathmale
  • mathmale
You're welcome!
arbyj
  • arbyj
for now lol
mathmale
  • mathmale
:)
arbyj
  • arbyj
i was moved to algebra 2 later in the week so i didnt fully learn how to do this part and some others
mathmale
  • mathmale
Hope to see you again here on OpenStudy!

Looking for something else?

Not the answer you are looking for? Search for more explanations.