The first answer is C. I did this by subtracting 40 from both sides which gave me: -3a=-63 Then I divided -3 from both sides which gave me a to equal 21.
The second answer would be 15. I did this by subtracting 3 from both sides which gave me: 1/5n=3 Then I multiplied by 5 on both sides. I took the reciprocal of 1/5 which is 5 and it gave me n to equal 15.
I hope this helped you! Let me know if you have any questions!
