Explanation:
When finding (x) not relating to a y=mx+b equation, start by setting your equation up to equal zero.
2x+7=0
Next you want to "isolate" the variable (get it by itself) as best as possible. Start by removing your extra number from the side of the equation where x resides. You may do this by opposing its symbol. ALWAYS MAKE SURE TO DO SOMETHING ON BOTH SIDES OF THE EQUAL SYMBOL!!
2x+7=0 -> subtract 7 from each side of the equal symbol so that the value still exists within the equation.
This would show:
(2x+7)-7=0-7
2x=-7
From here you want to continue isolating the variable.
Divide each side of the equal symbol by 2, so that we get rid of the coefficient, and arrive at what x truly equals by itself.
This would show:
2x/2=-7/2
x=

In conclusion, the value of x is -7/2 (negative 7 halves)