Math help in algabra inequalaties?

Question

Need more understanding on some more inequalaties and how you get them( dont think im stupid because i could do these using basic logic, its jsut that i want to know how to use the formulas to solve them.2 - x = 2 on this one i add 2 to both sides and end up with x = 4. i know this isnt the right answer. The next one is -8 - b = 11 i add 8 to 11 and get b = 19 but this isnt the right answer and i know this. how do i know if i add a ngative to the number on the other side, or add a positive, or vice versa. please help me out with this people. thank you everyone.

Wow thank you everyone for all the help you gave me. I really appreciate it. So i add always do the oposite of the sign. And for problems like 2-x= 2 i would do the oposite of 2 and subtract 2 from both sides and always leave that negative sign alone thats next to the x right?

Answer 1

To cut to the chase:-
Question 1
2 - x = 2
2 = 2 + x
x = 0
Question 2
- 8 - b = 11
- 8 = 11 + b
- 8 - 11 = b
b = - 19

Answer 2

I am not sure what you are asking.

If you have 2-x=2
then if you add two to both sides you would get:
2+2-x=2+2
4-x=4 which does not help you.

You need to subtract 2 from each side:
2-x=2
2-2-x=2-2
-x=0
then you can add x to each side or multiply both sides by negative 1.
-x+x=0+x
0=x
or -x(-1)=0(-1)
x=0

You need to do opposite of what the sign is.
The only thing is if you have something like -8-b=11 the -b is like saying + -b.
So if you add 8 to both side you have:
-8+8-b=11+8
0-b=19
-b=19
then multiply by -1
-b(-1)=19(-1)
b=-19

whatever you do to one side you have to do to the other if there is an equal sign.

Answer 3

there is a negative one in front of the x,that you have to divide out.

2 - x = 2, you have to subtract 2 here(not add)
-x = 0, usually you divide out the -1 but the answer is still 0

x = 0


-8 - b = 11, add 8
-b = 19, now divide by negative 1
b = -19



A few of my students get confused with the sign, thinking that
5 - x = 20, means a negative 5 and they have to add 5 to both sides. The sign is always in front, so you have to realize that x is negative and this is really a two step equation.

Answer 4

i see where you are messing up...on 2-x=2 since the left 2 is postitive you must subtract it from the two on the right, so 2-2=0. then you get -x=0 and you must get x to be positive so you divide both sides by a negative 1 (because the coefficient of x is -1) and you get x=0

on the second one you were right in adding 8 and 11 because 8 is negative so you must make it positive by adding. then you are left with -b=19 so you must get the b to be positive. divide both sides by a negative 1 and you get b=-19 because 19/-1 makes the number negative

so your final answers are x=0 and b= -19

Answer 5

-8 - b = 11
This is how you would do a problem like this imagine it as (-8)+(-b)=11. Now you would do as you said and add the 8 to both sides and you would end up with (-b)=19. Then from here to get -b to change to just "b", you would have to multiply both sides by -1, which would give you b=-19.

Answer 6

The basic rule here is
Equals added to equals are equal.
In the first problem make two sets of equations
2 - x = 2
-2 = -2
+_______
-x = 0 or x = 0

The second works out like this
-8 - b = 11
8 = 8
+_________

-b = 19, or b = -19

Answer 7

Think about what you are doing. "x" represents an unknown number.

Take 5 - x = 10, for example.
First we need to isolate the unknown variable. You do this by subtracting 5 from both sides.

- x = 5

You end up with a negative unknown number. To find the unknown number, multiply each side by -1.

x = -5

Answer 8

1. 2-x=2
2 is positive, so you need to subtract to get rid of it.
-x = 0
x = 0

2. -8-b=11
-b = 19
b = -19

Answer 9

2-x=2
if had two apples and took away x number of apples
and was left with two apples
what is the value of x
note if -x=0 then x=0
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lets go slow

-8-b=11
put the -8
on the other side
-b=11+8
-b=19
multiply both sides by -1
(plus*plus=plus minus*minus=plus plus*minus=minus)
b=19
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taking something over the other side

the cost of 4 apples + the cost of 1 pear=$1
so if one 1 pear costs 40 cents
then we have
the cost of 4 apples plus 40 cents=$1
so the cost of 4 apples=$1-40 cents
so each apple cost 60cents/4
thus apples are 15 cents each
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