How do you make denominators the same when subtracting fractions?

Let's take an example.

3/4 - 6/7

The denominators here are 4 & 7.

First you find the LCM (lowest common multiple) of both numbers.

Here is an easy way:
4 ---> 4, 8, 12, 16, 20, 24, 28, 32, 36, 40
7 ---> 7, 14, 21, 28, 35, 42, 49, 56, 63, 70

The least common multiple here is 28.

And so, you multiple both 7 and 4 (which are the denominators) with a number to get 28.

7*4= 28
4*7= 28

Make sure you also apply the same multiplication to the numerator.

So in conclusion:
3*7/4*7 & 6*4/7*4

I hope this helps.

The answer is c because you turn 17.5% into a decimal which gives you .175 then you times that by $361.35 which gives you 63.23625 but then you round that which gives you 63.24. then you at 63.24 pulse 361.35 and you round it which gives you $425