will the point (-8,-1) satisfy the inequality of x-y>10? yes or no?

Question

can you show me how to work this problem out?

Answer 1

The one point you mentioned does not satisfy the equation, but here is how to figure it out:

 

1)  x - y > 10

2) regular algebra - treat it like a normal equation, get "Y" by itself on the one side:

subtract x from both sides

 

3) x - x - y > 10 - x

4) -y > 10 - x

5) divide by -1 (don't forget to change the > to < because you are dividing by a negative!!)

6) y < -10 + x

 

7) now plug in an "x" value, let's say 2, y < -10 + 2 or y< 8.  This means all values below 8 are acceptable.  To plot, at x = 2, put a open circle on the 8 (meaning NOT EQUAL TO) and put a vertical line underneath it (to show that all Y values under 8 satisfy the inequality at that point of x = 2.

8) plug in another value of X and solve for Y.  Again, it is open circle because the inequality does not say < OR = TO (less than or equal to), it just says < (Less than) .

 

The rest should be easy.  Good luck!!

Answer 2

You just have to plug the numbers in and see if it is true. 

 

(x, y) = (-8, -1) 

 

0. Write out equation:                  x  -    y  > 10

 

1. Plug in values for x and y:     [-8] - [-1] > 10  

    

2. Simplify.                              [-8] + [1] > 10

 

3. Simplify                                          -7 > 10

 

4. Evaluate. Does this make sense? NO. -7 is less than 10, but the equation says it is greater than. 

 

 

Answer 3

Remember (X, Y), so x = -8 and y = -1.  place these into the x and y positions and see if it makes a true statement.

 

-8 - (-1) Greater than 10?

or

-8 + 1 Greater than 10?