Question 53415This question is from textbook Prentice Hall Mathematics Algebra 1
: What is -y + 10 = 25? I did:
-y + 10 = 25
-25 -25
-y = -15
-1(-y) = -1(-15)
y = 15
Am I right?
This question is from textbook Prentice Hall Mathematics Algebra 1
Found 3 solutions by consc198, ikleyn, MathTherapy:
Answer by consc198(59)   (Show Source):
Answer by ikleyn(53828)  (Show Source):
You can put this solution on YOUR website! .
This question is from textbook Prentice Hall Mathematics Algebra 1
What is -y + 10 = 25? I did:
-y + 10 = 25
-25 -25
-y = -15
-1(-y) = -1(-15)
y = 15
Am I right?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You are wrong.
The answer in the post by @consc198 is WRONG, too.
For correct solution see what follows.
Your starting equation is
-y + 10 = 25.
Move -y from left side to right side changing the sign
10 = 25 + y.
Move 25 from right side to left side changing the sign
10 - 25 = y.
Combine like terms in left side
-15 = y.
So, your answer is y = -15.
Solved correctly and completely to the end, with detailed explanations.
Answer by MathTherapy(10830)  (Show Source):
You can put this solution on YOUR website!
What is -y + 10 = 25? I did:
-y + 10 = 25
-25 -25
-y = -15
-1(-y) = -1(-15)
y = 15
Am I right?
***********
As @IKLEYN pointed out, the answer you came up with, and @consc198 agreed with: y = 15, is WRONG!
You stated: What is -y + 10 = 25? I did:
- y + 10 = 25
-25 -25 <=== Here, you should've SUBTRACTED 10 from each side, instead of 25
- y = - 15 <=== This is where you went WRONG
- y - 15 = 0 <=== This is what you should've had
- 15 = y ---- ADDing y to each side
A very EASY WAY is:
- y + 10 = 25
- 10 - 10 <=== Subtracting 10 from each side, to ISOLATE the variable
- y = 15
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