Answer :

so get all the x terms one side
when dealing with equations, do the same to both sides so the equation will stay equal
first group like terms
2x+5(-8)=12-10
negative times positive=negative
2x-40=2
add 40 to BOTH SIDES
2x=42
divide BOTH sides by 2
x=21
So,

2x + 5(-8) = 12 - 10

Distribute
2x - 40 = 12 - 10

Collect Like Terms
2x - 40 = 2

Add 40 to both sides
2x = 42

Divide both sides by 2
x = 21