14 - x = 42 ? Confused on how to solve this.

dvdlpt

New member
Joined
Jan 15, 2014
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2
Hello,

Need some help with understanding the above equation. I've learned we are supposed to inverse, or do the opposite to solve the above equation. However, when I apply this method to the above equation, I don't get a correct result. I know I'm missing something important. My math book doesn't have an example for this type of question.

My understanding is this;
14 - x = 42
x = 42 - 14 ?
x= 28

Clearly x does not equal 28. I know from checking the answers that x is actually (-28). What are the steps to solve this one?

Thanks for the help!
 
14 - x = 42
x = 42 - 14
How did the -x turn into a +x?

Instead, try doing the steps clearly:

Code:
14 - x = 42
   + x      + x
----------------
14     = 42 + x


14      =  42 + x
   - 42   -42
-----------------
14 - 42 =       x

...and so forth. ;)
 
Hello,

Need some help with understanding the above equation. I've learned we are supposed to inverse, or do the opposite to solve the above equation. However, when I apply this method to the above equation, I don't get a correct result. I know I'm missing something important. My math book doesn't have an example for this type of question.

My understanding is this;
14 - x = 42
x = 42 - 14 ? How did - x on the left hand side magically change into + x? See below
x= 28

Clearly x does not equal 28. I know from checking the answers that x is actually (-28). What are the steps to solve this one?

Thanks for the help!
14 - x = 42
- x = 42 - 14 = 28
(- 1) * (-x) = (-1) * 28
x = -28
 
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