Answer: N=15
Step-by-step explanation: This is because (4n-18) when solved needs to equal 42. So when solving this you would change the equation to 42=4n-18 and then you need to isolate n. In order to do that you do the opposite so your equation becomes 42+18=4n or (60)=4n. And then you divide 60/4 and get n by itself. Therefore N=15.