Can someone please take pity on my lack of math skill and help me understand something? I keep missing the same type of question, getting stuck at the same place. Perhaps I am not approaching the problem correctly, but for the life of me I can't get to the solution. Here are just 2 problem that can't solve, but I have missed 100% of every problem that ends up with an improper fraction as the answer to the variable.

1. 20x - 23 = 14x - 13
+13 to both sides
20x -10 = 14x
-14 from both sides
6x - 10 = x
(stuck)
the correct answer is 5/3

2. 42x + 40 = 7x
-7 both sides
35x + 40 = x
(stuck)
the correct answer is 8/7

__________________
Jennifer
ALM, Psychology, Harvard University, in progress
AA & BA, Social Sciences, Thomas Edison State College, 2008
AOS, Culinary Arts, Culinary Institute of America, 1990

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i find separating "x's" and numbers to each side of the equal sign to be easier to work with so if you wanna give it a try, here's how i would do it:

1) 20x - 23 = 14x - 13
-14x from both sides
6x - 23 = -13
+23 to both sides
6x = 10
divide 6 from both sides
x = 10/6
reduce to 5/3

2) 42x + 40 = 7x
-42x from both sides
40 = -35x
divide -35 from both sides
-8/7 = x or x = -8/7
(i'm pretty sure "x" is negative so can you please check your book again to make sure?)

hope this helps =]

__________________
Jenny =]

You are fairly close to the answer. You wrote down 6x - 10 = x. Remember though, that you have not isolated x yet. So, you should have written 6x - 10 = O. Then add 10 to both sides, which gives you 6x = 10..now, isolate the x by dividing by 6. Now you have x = 10/6, which reduces to 5/3.

Remember on problems such as these that you have to divide the number infront of the x to isolate the x, if that makes sense.

Your problem on the first is that you didn't get the x by itself on one side. Instead of subtracting 14 you should have subtracted 20 from both sides.
20x - 23 = 14x - 13
+ 23 to both sides
20X = 14X + 10
-14X from both sides
6X=10
Divide by 6 to get the answer
X = 10/6
X = 5/3


42x + 40 = 7x
When you subtracted 7X you should have gotten this:
35X + 40 = 0
- 40 from both sides
35X = -40
Divide both sides by 35
X = -40/35
X = -8/7 (The answer should be negative )

Hope this helps!

__________________
~DixieGirl~