Ok all you math people

JesusFrEaK0077 · 03-16-2007, 05:03 PM

HELPPPPPPPPPPPPP!!!!!!!!!!!
I've got Algebra 1 homework goin and I got a question... Any one help me with it maybe?

LefseRae · 03-16-2007, 05:16 PM

I kin try....

JesusFrEaK0077 · 03-16-2007, 05:21 PM

Problem is...

2X-5(8-7X)=7 ... solve for X and the first step is using distributive property with the -5(8-7X)... If I can get past that part. I can do the rest. But I completely suck at distributive property.

Nate · 03-16-2007, 05:34 PM

Quote:

Originally Posted by JesusFrEaK0077

Problem is...

2X-5(8-7X)=7 ... solve for X and the first step is using distributive property with the -5(8-7X)... If I can get past that part. I can do the rest. But I completely suck at distributive property.

The distributive property would have you come up with -5*8 + -5*-7x (just multiply the thing in front of the parentheses [in this case -5] by both of the things inside the parentheses [in this case 8 and -7x] and then add them up [remember that a negative-negative is a positive]), or -40 + 35x.

Plugging that back into your equation and solving:

2x - 40 + 35x = 7

37x - 40 = 7

37x = 47

x = 47/37

JesusFrEaK0077 · 03-16-2007, 05:42 PM

Quote:

Originally Posted by Nate

The distributive property would have you come up with -5*8 + -5*-7x (just multiply the thing in front of the parentheses [in this case -5] by both of the things inside the parentheses [in this case 8 and -7x] and then add them up [remember that a negative-negative is a positive]), or -40 + 35x.

Plugging that back into your equation and solving:

2x - 40 + 35x = 7

37x - 40 = 7

37x = 47

x = 47/37

ok, so you you would include the negative on -7X to the -5 times -7X?
That is the part I was VERY confused with.
And when I had solved the equation before. It was 47/-37

Chem6Afreak · 03-16-2007, 05:43 PM

2X-5(8-7X)=7
2X+-5(8+-7X)=7
2X+-40+35X=7
37X+-40=7
+40 = +40
37X=47
X=47/37
When you first start the equation make each subraction simbol positve(istead of minus 3, say, plus -3) it will help you with the distributive property.

JesusFrEaK0077 · 03-16-2007, 05:45 PM

Quote:

Originally Posted by Chem6Afreak

2X-5(8-7X)=7
2X+-5(8+-7X)=7
2X+-40+35X=7
37X+-40=7
+40 = +40
37X=7
X=7/37

crap sorry everybody.. there's a negative in front of the 2X in the beginning.. the problem is actually -2X-5(8-7X)=7... I just now noticed that.. I'm very sorry!

Chem6Afreak · 03-16-2007, 05:51 PM

-2X-5(8-7X)=7
-2X+-5(8+-7X)=7
-2X+-40+35X=7
33X+-40=7
+40 = +40
33X=47
X=47/33

Chem6Afreak · 03-16-2007, 05:51 PM

no problem

JesusFrEaK0077 · 03-16-2007, 05:53 PM

Quote:

Originally Posted by Chem6Afreak

-2X-5(8-7X)=7
-2X+-5(8+-7X)=7
-2X+-40+35X=7
33X+-40=7
+40 = +40
33X=47
X=47/33

ok, now that's what I got... but why did you add all those pluses in there?

Chem6Afreak · 03-16-2007, 06:02 PM

Well, since X+-5 is the same as X-5 it doesnt matter whether you change the signs, it just makes the algebra more clearer and easier.

5-(2--2)=X minus negitive 2
5-(2+2)=X
5-1(2+2)=X there is always a one outside the perenthcise.
5+-1(2+2)=x
5+-2+-2=x to me thats easier than 5-2-2=x
thats pretty much the only reason you would change subtraction to addition
finish the promblem and x=1

JesusFrEaK0077 · 03-16-2007, 06:08 PM

ohh.. ok..

I have another question. What's the fraction for .94? I've been trying to get it for about 10 min. and I can't figure out what it is..

Chem6Afreak · 03-16-2007, 09:29 PM

21/25

SccHarpGirl · 03-16-2007, 09:58 PM

Chem, that's the fraction for .84 ;-)

The fraction I get for .94 is 47/50. Just write it as 94/100 and then divide both sides by 2...you can't do more than that since 47 is a prime number.

Chem6Afreak · 03-17-2007, 10:08 AM

my fault. Just a little mis-calculation.