Answer:
You want to get all of the equations into standard form:
ax+b
with a being the coefficient and b being the constant.
so the first one is correct
For equations 2 and 3 you want to make the denominators the same so that you can add them.
for (1/4)x and -(1/12)x you can make the denominator twelve and for the constants you can make the denominator 10.
for (1/18)x and (1/9)x you can make the denominator 18, and the constant is already there, no work needed