2x + 52 = 99 subtract 52 from each side
2x = 47 divide each side by 2
x = 47 / 2
To solve this problem, you must isolate the variable on one of the two sides, preferably the left side. To do so, you must look at the equation. Is the side with the variable in that expression adding or subtracting the 52? It's adding it, so you must do the inverse, or opposite, of addition to both sides. This will leave you with 2x=47. From here, you must keep up the habit of doing the same thing to both sides, and you must isolate the variable yet again, so this time you must do the inverse of division to isolate your variable. 2x/2 and 47/2 will in the end product give you x=23.5.