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Oh yes, my first day on ALEKS...you guys are going to get sick of me fast hilarious
I can't figure out a problem type and even when I click explain, it doesn't really explain the part that I don't understand. Help!
The problem type is: X and Y intercepts of a line given the equasion in standard form
find x and y
Here is a sample that I am having trouble with and what I am doing:
6.8x + 2.4y+9.9=0
step 1: make x=0 to solve for y
6.8*0 + 2.4y+9.9=0
2.4y+9.9=0
here is where I get stuck.
this is what I write : Y= 9.9/2.4
but ALEKS makes the 9.9 negative.
Why?
When I solve for x and make the y=0 it's the same trouble.
6.8x + 2.4*0+9.9=0
6.8x + 9.9 = 0
this is what I write: X= 9.9/6.8
but ALEKS makes the 9.9 negative.
so my answers were
x=4.13
y=1.46
of course both are wrong because they should be negative. Clearly there is some mathy thing that I don't know but must be obvious to other people because there is no help button there. Help :confused:
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12-07-2009, 10:17 PM
(This post was last modified: 12-07-2009, 10:51 PM by peace123.)
you wrote  tep 1: make x=0 to solve for y
6.8*0 + 2.4y+9.9=0
2.4y+9.9=0
here is where I get stuck.
this is what I write : Y= 9.9/2.4
but ALEKS makes the 9.9 negative.
Why?
~~~~~~~~~~~
2.4y+9.9=0
then subtract 9.9 from both sides
so 2.4 y = -9.9
then divide each side by 2.4
I hope that make sense. Math is not my strongest area, but that is the way I see that problem
Edited>> based on jaer57 reply , I edited the above , so it would not confuse you, or future readers >> sorry, as I said math is not my strongest subject
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peace123 Wrote:you wrote tep 1: make x=0 to solve for y
6.8*0 + 2.4y+9.9=0
2.4y+9.9=0
here is where I get stuck.
this is what I write : Y= 9.9/2.4
but ALEKS makes the 9.9 negative.
Why?
~~~~~~~~~~~
you have to divide the 2.4y by 2.4 and the zero by 2.4
so that give you
y+9.9=0
then subtract 9.9 from both sides
so y = -9.9
I hope that make sense. Math is not my strongest area, but that is the way I see that problem
omg you rock. thanks a zillion
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12-07-2009, 10:36 PM
(This post was last modified: 12-07-2009, 11:04 PM by jaer57.)
If you put the equation into the slope-intercept equation, it makes it a little easier:
y= mx + b
Putting 6.8x + 2.4y + 9.9 = 0 in that form would give you:
-2.4y = 6.8x + 9.9
You can get y by making x = 0:
-2.4y = 6.8(0) + 9.9
-2.4y = 9.9
y = 9.9/-2.4
y = -4.125
You can get x by making y = 0:
-2.4(0) = 6.8x + 9.9
0 = 6.8x + 9.9
-9.9 = 6.8x
x = -9.9/6.8
x = -1.456
Both of those answers are the x and y intercepts. I think you were doing it right, but maybe forgot to change the sign when you subtracted from zero. Does that make it any easier?
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jaer57 Wrote:If you put the equation into the slope-intercept equation, it makes it a little easier:
y= mx + b
Putting 6.8x + 2.4y + 9.9 = 0 in that form would give you:
-2.4y = 6.8x + 9.9
You can get y by making x = 0:
-2.4y = 6.8(0) + 9.9
-2.4y = 9.9
y = 9.9/-2.4
y = -4.125
You can get x by making y = 0:
-2.4(0) = 6.8x + 9.9
0 = 6.8x + 9.9
-9.9 = 6.8x
x = -9.9/6.8
x = -1.456
Both of those answers are the x and y intercepts. I think you were doing it right, but maybe forgot to change the sign when you subtracted from zero. Does that make it any easier?
Why is the 2.4 negative when you start? Otherwise, I understand what you are showing me.
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12-08-2009, 11:31 AM
(This post was last modified: 12-08-2009, 11:41 AM by TMW2010.)
cookderosa Wrote:Why is the 2.4 negative when you start? Otherwise, I understand what you are showing me.
When you move a value from one side of the equal sign to the other, it takes on the opposite sign. If you move a positive number to the other side of the equal sign, it becomes negative. If you move a negative number to the other side, it becomes positive.
Quote:Putting 6.8x + 2.4y + 9.9 = 0 in that form would give you:
-2.4y = 6.8x + 9.9
Is the same as saying 6.8x + 9.9 = -2.4y but since you're solving for y, and since we're used to reading left to right, we're more accustomed to putting the value that we're solving for on the left.
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PLEASE keep posting the problems. It will help me with the College Math exam.
Thanks.
As a matter of fact, I think we should have a new forum category for Math questions and problems!!!!! :0
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.....oh yeah, thanks TMW2010. You're brilliant! Such a clear explanation, even I can understand it.
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cate
BS (UMUC) in 2010, 30+ years in the making!!
Intro to Computing 63
Astronomy 63
Technical Writing 62
Principles of Mgt 71
Principles of Marketing 68
Substance Abuse 467
College Math 56
Principles of Finance 425
Principles of Statistics 458
Exams: ALL DONE!!!!!!!!!!
GRADUATION--UMUC--MAY 15, 2010 (unbelievable)
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TMW2010 Wrote:When you move a value from one side of the equal sign to the other, it takes on the opposite sign. If you move a positive number to the other side of the equal sign, it becomes negative. If you move a negative number to the other side, it becomes positive.
Is the same as saying 6.8x + 9.9 = -2.4y but since you're solving for y, and since we're used to reading left to right, we're more accustomed to putting the value that we're solving for on the left.
>>
Ahhhhhh ok, I get it. It was right in front of me lol. Thanks everyone!
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