SOLUTION: Would you please show me what steps I am either leaving out or doing wrong in the following equation: {{{(5x+1)/7 - (2x-6)/4 >-4}}}. My answer does not match the one in the book.

Algebra ->  Equations -> SOLUTION: Would you please show me what steps I am either leaving out or doing wrong in the following equation: {{{(5x+1)/7 - (2x-6)/4 >-4}}}. My answer does not match the one in the book.      Log On


   



Question 199942This question is from textbook Intermediate Algebra
: Would you please show me what steps I am either leaving out or doing wrong in the following equation: %285x%2B1%29%2F7+-+%282x-6%29%2F4+%3E-4. My answer does not match the one in the book. Thank you. This question is from textbook Intermediate Algebra

Found 2 solutions by RAY100, Edwin McCravy:
Answer by RAY100(1637) About Me  (Show Source):
You can put this solution on YOUR website!
Revised due to problem statement revision
.
(5x+1) / 7 - (2x-6) / 4 > -4
.
4(5x+1) /28 - 7(2x-6)/28 > -4
.
( 20x +4 -14x +42) / 28 > -4
.
( 6x +46) / 28 > -4
.
6x + 46 > -4 * 28
.
6x +46 > -112
.
6x > -158
.
x> -26 1/3
.

Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
Ray's solution is incorrect.
Here is the correct solution by Edwin:

%285x%2B1%29%2F7+-+%282x-6%29%2F4+%3E-4


We will clear of fractions.

Put parentheses around each term and write the 
-4 on the right as -4%2F1 so
that every term will be a fraction:

 %28%285x%2B1%29%2F7%29+-+%28%282x-6%29%2F4%29+%3E%28-4%2F1%29

The LCD of all the denominators is 28
Multiply every term through by 28%2F1

 

Cancel the 7 into the 28, getting 4

 

Cancel the 4 into the 28 in the second term, getting 7

 

Multiply the 28 by the -4 on the right getting -112

 

What's left is

4%285x%2B1%29+-+7%282x-6%29+%3E+-112

The we remove the parentheses by distributing:

20x%2B4+-+14x%2B42+%3E+-112

6x%2B46%3E-112

6x%3E-112-46

6x%3E-158

x%3E-158%2F6

x%3E-79%2F3

The solution set in interval notation is (-79%2F3,infinity)

Edwin