Question

One number is 12 more than another. The sum of the smaller number and twice the larger number is 39. Find the larger number.

This is what I have so far:
x+y+12=39

Answer 1

You just have an extra variable.

x = the smaller number
x + 12 = the larger number

Now, write the equation according to the sentence "the sum of the..." and solve.

Answer 2

This is how I worked it:
n+12=m
n=m+12

m=5
m=17

Answer 3

I don't see how you got the answer from that, unless you guessed and checked. Your answers are correct by plugging them into the sentence.

I would have written this equation and then solved:

x + 2(x+12) = 39