C. a + 3
10 + 3 = 13
11 + 3 = 14
12 + 3 = 15
a + 3 = ?
When it says x and y are directly related it means that x is multiplied by something to get y. To solve you divide y by x which is 840 divided by 6. Which is 140 then you multiply and solve so the y value for 5 is 700. The x value for 420 is 3 and the y value for 4 is 560.
If you would like to know the value of the 2.9% tax, you can calculate this using the following steps:
2.9% tax of $46 shoes = 2.9% * 46 = 2.9/100 * 46 = $1.334
If you would like to know what is the whole price you have to pay for the shoes (including the tax), you have to add $46 and $1.334:
$46 + $1.334 = $47.334
The expression would be (5*6)+(5*6)=x
or you could shorten it and do (10*6)=x