6-x-x=18 i'm not sure how to solve this problem i keep getting -9 but i'm not sure

The ratio of rock songs to dance songs on jonathan’s mp3 player is 5: 6. the total number of rock and dance songs jonathan has is between 101 120. how many rock songs does he have?

Find the equation of the ellipse with the following properties. the ellipse with foci at (0, 6) and (0, -6); y-intercepts (0, 8) and (0, -8).edit: the answer is x^2 over 28 + y^2 over 64 = 1

If we pull out the middle player of team a and the fourth player of the team b. what will be the force of team a and team b? what is their sum of forces