In Algebra what is the different between these two?

Question

-4+(-5)=-9

But then what is this one -5-2=?

I don't understand the use of the parentheses...aren't these the same questions?

Answer 1

the parentheses aren't there to confuse you, they are there to CLARIFY! They break up the plus and minus signs so you can coherently read the equation.

for example, the fist question saying:

I have negative four... to that I wish to add negative five... therefore it can be reworded as negative four minus five (plus sign and a minus sign cancel out to equal a minus), which equals negative nine.

but the second question is saying:

I have negative five... to that I wish to subtract positive two... negative five minus two equals negative seven.

again, a plus sign and a minus sign cancel out to equal a minus... the plus sign is not written in the second one, but you could insert it into a bracket before the negative sign and it would still be correct e.g., -5 -(+2).

Answer 2

-4 + -5 is a -9 since 2 negitives added together equal a negative
and a negative and a positive added together are like subtracting the two

6+-2 = 4

-5-2 is saying a negative 5 minus a negative 2. Since you have a positive 5 and you don't have any negitives you have to add the negitive so it would be a negitive 7. If it helps try the plus opposite thing.

Plus Opposite Example:

-5-2

You can do plus opposite...

so -5 + -2

Since there's a negitive before a number, you can change the subtraction sign into a positive, but then after that plus sign u must add a negitive

Answer 3

-4 + (-5) can be written as -4 - 5 because + (-5) = - 5

The reason for the use of parenthesis in this case is to avoid confusion on the operation - the plus sign and the sign of the number - the negative sign.

Therefore -5 - 2 = -5 + (-2) = -5 - (2)

Although we seldom put a parentheses for positive numbers.

I hope this would be helpful.

Answer 4

These are the same, you can also write it this way -5+(-2)= -7

but one way we can clear up the confusion is if there is a negative sign in front of the parentheses. for example -5 -2= -7 but -5 -(-2) = -3 because two negatives become a positive.
I hope this helps.

Answer 5

Parenthese are normally used to indicate the order of an operation. IE:

(5 + 8) * 7

is different from

5 + 8 * 7

In your example, the parenthese really don't do anything. The first expression could be rewritten as:

-4 -5 = -9

The second expression is

-5 -2 = -7

so, they really are different things

Answer 6

The parenthesis multiplys what's out in front of it... -4+(-5) the -5 is multiplied to the + out in front of it which becomes -4-5 and two of the same sign are added but the sign remains the same which =-9...-5-2=-7 because the same signs are added and kept.

Answer 7

in Alegebra, You use positive and Negative numbers.

Which means, you can add, subtract, mulitply positive and negative numbers with each other.

1 + (-1) = 0 This is because they cancel each other out.

Therefor, (-4) + (-5) = (-9) Because your adding two negative numbers together. This equation is correct.

(-5) - (+2) = (-7)
This is because your are subtracting a positive number. Therfor, the answer is negative 7

Answer 8

-5-2=-7

Answer 9

They're saying the same thing, only slightly differently...
The plus sign helps one to understand the addition of 2 negative numbers resulting in a lesser negative number... The other demonstrates the lessening of a negative number by subtracting from it... Essentially, it's the same thing...

Answer 10

the parenthesis are just to separate the - (in -5) and the + (in the equation) otherwise it would look like -4 + -5= -9 and it would be kinda confiusing, they are just trying to make it easier for you.