Y2-y1/x2-x1
8-[-13]/17-17
21/0
this is called undefined because its denominator is zero.
3x + 7 = x
First, subtract 3x from both sides. / Your problem should look like: 7 = x - 3x
Second, simplify x - 3x to -2x. / Your problem should look like: 7 = -2x
Third, divide both sides by -2. / Your problem should look like:

= x
Fourth, simplify

to

/ Your problem should look like:

= x
Fifth, switch sides. / Your problem should look like: x =

Answer as fraction:

Answer as decimal: -3.5
Distance formula : d = sqrt (x2 - x1)^2 + (y2 - y1)^2
(-5,8)(10,-7)
d = sqrt (10 - (-5)^2 + (-7 - 8)^2
d = sqrt (10 + 5)^2 + (- 15^2)
d = sqrt (15^2) + (-15^2)
d = sqrt 225 + 225
d = sqrt 450
d = 21.21
The volume of number three is 63.7