What numbers would you subtract from each side of the equation x + 12 = 17 + 3 to get the variable by itself ?

The number you would subtract on both sides would be 12... but this in  and of itself is not the first step. the way you would solve this is by:
combine like terms. x + 12=20
then, subtract 12 from both sides to get variable alone.
you will end up with a final answer of x=8

Ok so basically when you work with equations you want to do the opposite regardless if the sign is adding or subtracting do the opposite. Ok so x+12=17+3 So first we can not simplify the numbers on the left side so we leave it. Now 17+3 is 20 so x+12=20 do the inverse because you want to get x by itself to see what its secret number is. so 20-12 is 8 x=8 hoped that helped .:))