First get y by its self , then graph , find intersection point and plug in x and y to both equations, see if it makes sense , then the solution must be you intersection point
Well the sum is 15+6=21. then you must do 81-21=60. So your answer must be t=60.
First day = 10 +8
=18
second day = 8+8
=16
3rd=16
4th= 16
5th=16
6th=16
16+16+16+16+16+18
=80+18
=98
Answer: x = 1
3x + 4 = 7
subtract 4 from both sides
3x = 3
x = 3/3 = 1