SOLUTION: 3(x-1) = 4 (-x + 5) solve for X? Is there a site that states the rules for solving this? I want to help my son?

Algebra ->  Formulas -> SOLUTION: 3(x-1) = 4 (-x + 5) solve for X? Is there a site that states the rules for solving this? I want to help my son?       Log On


   

Question 826616: 3(x-1) = 4 (-x + 5) solve for X? Is there a site that states the rules for solving this? I want to help my son?
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Choose a Beginning Algebra book; not a site.
You would benefit from studying properties of numbers. The equation you show would use Distributive Property, Additive Inverses, and Multiplicative Inverse. Understanding signed numbers is also necessary.

The goal for the given equation is get all terms of x on one side and all constants on the other side.

3x-1=-4x+20---(This line has a mistake, but...) ------ Distributive Property
3x-1+1=-4x+20+1 ------ Additive Inverse
3x-1+1+4x=-4x+20+1+4x ------Additive Inverse
3x+4x-1+1=-4x+4x+20+1 --------Commutative Property for Addition
Good Time To Simplify or Compute the Parts worth Computing...
7x+0=0+21 ---------- Meaning of Additive Inverses
7x=21 --------- Zero is the Additive Identity Element
7x(1/7)=21(1/7) --------Multiplicative Inverse
x=3

--The above steps already posted and person had read it. Here is the work without the mistake:
--
3x-3=-4x+20---(Mistake Fixed...) ------ Distributive Property
3x-3+1=-4x+20+1 ------ Additive Inverse
3x-3+1+4x=-4x+20+1+4x ------Additive Inverse
3x+4x-3+1=-4x+4x+20+1-------Commutative Property for Addition
7x-3+1=0+20+1-------Combined like-terms, and Property of Additive Inverses
Now a Good Time to Simplify...
7x-2=21
7x=21+2 -----------Additive Inverse
7x=23
(1/7)7x=(1/7)23-----------Multiplicative Inverse
x=23/7

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
3(x-1) = 4 (-x + 5) solve for X? Is there a site that states the rules for solving this? I want to help my son?
Considering that X is the same as x, we get:

3(x - 1) = 4(- x + 5)

3x - 3 = - 4x + 20 ------- Distributing both sides of equation 

3x + 4x = 20 + 3 ------- Applying ADDITIVE INVERSE of - 3, and - 4x

7x = 23

x+=+23%2F7, or highlight_green%28x+=+3%262%2F7%29

You can do the check!! 



Send comments, “thank-yous,” and inquiries to “D” at MathMadEzy@aol.com.

Further help is available, online or in-person, for a fee, obviously. 

	

For FREE info and answers to questions about the ASVAB exam, the NYS 3 – 8 city/state wide exams, 

GENERAL MATH QUESTIONS, MATH HOMEWORK QUESTIONS, or MATH QUESTIONS related to the Regents Integrated Algebra,

Regents Geometry, Regents Algebra 2/Trigonometry, SHSAT, COOP/HSPT/TACHS, PSAT, SAT, ACT, SSAT/ISEE, GRE, CLEP,

and the GED, you can visit: http://asvabstudyzone.freeforums.net/.