# algebra

posted by on .

how do you work this problem ????

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X+(-9)=-5

• algebra - ,

x + (-9) = -5
x = -5 + 9
x = 4

• algebra - ,

but why does X = -5 +9

• algebra - ,

If A = B, then that implies that:

A + a = B + a

for any number a.

So, if

X + (-9) = -5

then choosing a = 9 we get:

X + (-9) + 9 = -5 + 9

Since (-9) + 9 = 0 we have

X = -5 + 9

• algebra - ,

You need to get the unknown on one side of the equation and the knowns on the other side. To do that you subtract -9 from the left side, change the sign and add it to the right side.

• algebra - ,

i still don't get it

• algebra - ,

ii still don't get it

• algebra - ,

Let's try this.

X+(-9)=-5

Remember, you can do anything to an equation as long as you do it to both sides. We want to get X (the unknown) on one side and the numbers on the other with the = sign between.
So, remove the parentheses first to obtain (remember that a + sign in front of the parentheses leaves the sign of the numbers inside the parentheses unchanged--conversely, a - sign in front of the parentheses changes all the signs inside the parentheses when the parentheses are removed).
X - 9 = -5
Now add +0 to both sides.
X-9+9 = -5+9
Now combine the numbers
-9 and +9 add to zero on the left while -5 and +9 add to +4 on the right.
X = +4.
That is the way to move anything from one side to the other. If you wish to move a + number simply subtract that number from both sides; if you wish to move a - number simply add that number to both sides. An easier way is to move anything from one side to the other by moving it and changing the sign.
I hope this helps.

• algebra - ,

yes thanx now i get it