Thursday

January 29, 2015

January 29, 2015

Posted by **Caroline** on Wednesday, September 19, 2012 at 9:11pm.

Will someone please check to see if I am doing this correct?

1.|7x+2|=10

x= (8/7) or (-12/7)

2.|3x-5|=-1

I got "no solution" because "d" cannot be negative.

3.|x^2-2x-16|=8

x= 6,-4 or x=4,-2

4.|3x-2|=7

x= 3 or (-5/3)

5.|x^2+2x+1|=-4

I got "no solution" because "d" cannot be negative.

6.|3x+2|+3=0

|3x+2|=-3

Again, I got "no solution" because "d" cannot be negative.

These I don't understand how to do.

7.|3x-1|=|x+4|

8.|(3)/(k-1)|=4

- Algebra 2 -
**David Q/R**, Thursday, September 20, 2012 at 4:59pmI agree with all your answers, if by "d" you mean the left hand side of the equation.

Regarding no. 7, I suggest you do something like this:

Each side of the equation inside the "absolute bars" could be either positive or negative. Try assuming that each side is one or the other, and try out all four possibilities - like this:

Suppose they're both positive:

3x - 1 = x + 4, so 2x = 5, so x = 5/2. Check it: |15/2 - 1| = |5/2 + 4| Correct.

Suppose the left hand side is positive, but the right hand side is negative:

3x - 1 = -x - 4, so 4x = -3, so x = -3/4. Check it: |-9/4 - 1| = |-3/4 + 4| Correct.

Suppose the left hand side is negative, but the right hand side is positive:

-3x + 1 = x + 4, so -4x = 3, so x = -3/4. But that's just the same as the one above.

Suppose the left hand side and the right hand side are both negative:

-3x + 1 = -x - 4, so 2x = 5, so x = 5/2. But that's just the same as the first one.

So there are two possible answers: x = 5/2 and x = -3/4. (Generally you'll find that you will always get the same two answers from the third and fourth one, because if you negate the entire equation you'll get the earlier solution. It's like saying if -x = -3 then x = 3)

For no. 8, if |3/(k-1)| = 4, then 3/(k-1) equals either +4 or -4. So (k-1)/3 = +4 or -4, so k-1 = +3/4 or -3/4. So k = 1 + 3/4 or 1 - 3/4.

**Answer this Question**

**Related Questions**

Math - I am really have a tough time trying to solve this problem. I think my ...

Algebra - check to see if correct - 5/(y-3)=(y+7)/(2y-6) i got no solution and i...

Physics - A capacitor is made from two 1.2 cm diameter coins separated by a 0.18...

Algebra-please check - What is the solution for absolute value of -1 + x = 5 I ...

Algebra - |3x+8|=20; -4 Basically that 4 is asking whether that is a possible ...

Algebra-help please - I already asked this question once about the absolute ...

algebra 3 - which number is a the solution of the equation [5x-2] = 8? a.}6/5 b...

Math-Algebra-Please check - What is the solution of 3 times the absolute value ...

Algebra, ( Check please) - 5h-7=2(h+1) I got, 5h-7=2h+1 and then I added -7 plus...

algebra 2 - evaluate:-[a-3b],if a= -2 and b= 6 -[-2-18] -[20] 20 correct? these ...