Find the value of x and kl if k is between j and l "jk=2x, kl=x+2, and jl =5x-10"

First, your equation would be set  up like this: 2x+x+2=5x-10. Then you would combine like terms. So:
2x+(1)x is 3x
3x +2=5x-10.
Then  you would combine like terms on opposite sides. This requires you to subtract the lesser number (Of the number/variable). So:
5x-3x = 2x
Now you have 2= 2x-10
Then add 10 on both sides (inverse operations)
now you have 12= 2x
Dived for x. X equals 6 
NOW PLUG IT BACK IN THE EQUATION! 
KL is x+2. = 6+2 is 8
Answers:
x= 6
KL = 8


Now, for checking your answers, solve x for everything. 
so the equation for checking would be 2(6)+6+2=5(6)-10
And then order of operations:
12+6+2=30-10
20 = 30-10
20=20

Happy Solving!