# How to calculate the value of C, if -C=1?

#### Indranil

##### Junior Member
How to calculate the value of C, If -C=1?

#### ksdhart2

##### Full Member
How to calculate the value of C, If -C=1?
Here's a big hint that will take you almost all of the way: -C is notational shorthand for (-1)C.

#### Indranil

##### Junior Member
Here's a big hint that will take you almost all of the way: -C is notational shorthand for (-1)C.
I am doing the calculation here below
or, -C=1
or, (-1)C=1
or, C=1/-1
or, C=-1/1=-1
Please check my steps if I am wrong.

#### HallsofIvy

##### Elite Member
I am doing the calculation here below
or, -C=1
or, (-1)C=1
or, C=1/-1
or, C=-1/1=-1
Please check my steps if I am wrong.
That is correct. Another way to approach it is to multiply both sides by -1 since (-1)(-1)= 1.

#### Jomo

##### Elite Member
I am doing the calculation here below
or, -C=1
or, (-1)C=1
or, C=1/-1
or, C=-1/1=-1
Please check my steps if I am wrong.
Another way to do this is to realize if two quantities are equal, then if you change their signs they will still be equal.

Some examples: 2 = 2 so -2 = -2. -9 = -9 so 9 = 9. .01 = .01 so -.01 = -.01. Now if -C = 1 just change both signs and get C = -1.

Now why does this work? It is equivalent to multiplying both sides by (-1) (as already pointed out)

Thank you all.