Pre-Algebra help

[midas]

I'm usually not bad with math, but these 2 pre-algebra problems have me stumped. Can anyone help. Thanks.

1) 32 + 2x < -4x + 6(5 + x)

2) 3cz + c = 9cz + 5 Solve for c

 

[rchristiansen]

I'm usually not bad with math, but these 2 pre-algebra problems have me stumped. Can anyone help. Thanks.

1) 32 + 2x < -4x + 6(5 + x)

2) 3cz + c = 9cz + 5 Solve for c

Without giving you the answer - try these hints

1 - Multiply out 6 times (5+x) THEN you should have a -4x and 6x to add together. Solve from there.

2 - When you are solving for c, the letter z will actually be in the answer. Also you might need to divide by c.

Good luck!

 

[midas]

Without giving you the answer - try these hints

1 - Multiply out 6 times (5+x) THEN you should have a -4x and 6x to add together. Solve from there.

2 - When you are solving for c, the letter z will actually be in the answer. Also you might need to divide by c.

Good luck!

These are DS homework problems.

1 - He got as far as 32 + 2x = 2x + 30, then subtract 30 from each side to get 2 + 2x = 2x. This where he (and I get stuck). If you subtract 2x from each side, you get 2 = 0x? 0 doesn't work if you plug it into the equation.

2 - We have no clue. The cz and c is what gets me.

He said he would ask his teacher in the morning but it's driving me crazy. If you give me more hints, I swear not to tell him.

 

[lacrosse_lady72]

IDK about 1, but for 2:
3cz+c=9cz+5
-9cz on both sides
-6cz+c=5
factor out c
c(-6z+1)=5
divide by -6z+1
c=5/(-6z+1)
... you cannot reduce this further.

For 1, I really don't know. Because it's weird that there would be 0x (this is what I end up with too, after a few ways of doing it). Do you have all the signs right? I'm really bad about that.

 

[java]

I don't know but can it be
C=6cz+5?
What grade is this?
My son said solve for z first as his clue.

 

[BCDisneyFanatic]

1) 32 + 2x < -4x + 6(5 + x)

You're right to be confused!

Expand to get: 32 + 2x < -4x + 30 + 6x

Combine like terms:

32 + 2x < 30 + 2x

Subtract 2x from both sides

32 < 30 Which is obviously not true. Therefore, there is no possible solution for x that will make this equation valid.

Lacrosse_Lady gave a very nice explanation for #2

 

[ckret01]

found this on the web for #2

3cz + c = 9cz + 5, solve this equations for c.

1. Combine like terms.
There are two different variables containing terms in this equation, the ones with variables cz and the ones with c. We begin by combining all like terms.


3cz + c = 9cz + 5
3cz + c – 9cz = 9cz + 5 – 9cz
c – 6cz = 5



2. Isolate the terms that contain the variable you wish to solve for.
The terms containing the variable c are already on one side of the equation. c – 6cz = 5

3. Isolate the variable you wish to solve for.
To isolate c, we first use the distributive property to pull c from both terms on the left side of the equation. We then divide both sides of the equation by the expression (1– 6z).


c – 6cz = 5
c (1– 6z) ¸ (1– 6z) = 5 ¸ (1– 6z)
c = 5/(1– 6z)

 

[tonilea]

err, I wrote it down wrong, nevermind. doh!

 

[rchristiansen]

32 + 2x < -4x + 6(5 + x) ==

I didn't solve the problem all the way through at first, but when you plug in a number for x, it doesn't work. I think the problem is wrong.

for example - plug in x = 2

you get

36 is less than or greater than 34, which obviously is false.

 

[BCDisneyFanatic]

32 + 2x < -4x + 6(5 + x) ==

I didn't solve the problem all the way through at first, but when you plug in a number for x, it doesn't work. I think the problem is wrong.

for example - plug in x = 2

you get

36 is less than or greater than 34, which obviously is false.

It's not that the question is 'wrong', it just means that there is no possible solution for x. I would put it more into the category of a 'trick' question.

 

[tonilea]

Other poster already fixed her answer

Thanks! I tried to get it off there as quickly as possible so my stupidity wouldn't be here for eternity.

 

[midas]

This is 6th grade pre-algebra.
This problem came off a worksheet from Kuta Software - Infinite Pre -Algebra.

I doublechecked and the problem (#1) is posted as it is on the worksheet. I could not get an answer either.

ckret01 - I got to c - 6cz = 5 but couldn't get anything that made sense from there. Thanks.

 

[lacrosse_lady72]

32 + 2x < -4x + 6(5 + x) ==

I didn't solve the problem all the way through at first, but when you plug in a number for x, it doesn't work. I think the problem is wrong.

for example - plug in x = 2

you get

36 is less than or greater than 34, which obviously is false.

I agree because the most I've been able to reduce it to is 16+x<15+x, which is not possible. Maybe OP can set us straight .

 

[lacrosse_lady72]

This is 6th grade pre-algebra.
This problem came off a worksheet from Kuta Software - Infinite Pre -Algebra.

I doublechecked and the problem (#1) is posted as it is on the worksheet. I could not get an answer either.

ckret01 - I got to c - 6cz = 5 but couldn't get anything that made sense from there. Thanks.

Is there a way to put "no solution"?

 

[BCDisneyFanatic]

Thanks! I tried to get it off there as quickly as possible so my stupidity wouldn't be here for eternity.

Yeah, I've posted a few mistakes myself over the years. Gotta love that D'oh moment!

 

[midas]

Thanks everyone for your help. I was the one going crazy trying to figure it out, DS could care less

 

[donnajon]

let me think some more.

 

[wdwmom0f3]

You may find this funny, but when I have trouble helping my children with any kind of math, I turn to youtube. Normally there are examples close enough on there to help me understand so that I can help my child.

As for this problem, daddy would have to help.