Plz help Elimination method

1.
3x-5y=3
4x-15=-21

2.
28x+13y=41
17x-91y=-71

3. 1000 tickets were sold for a school play. The regular price tickets were $5. Tickets for reserved seating was $2 more. The box office took in a total of $5300. How many tickets of each type were sold?

One month, a music site observed that 60% of the people who downloaded songs from its site downloaded q sam's latest single. the equation below represents this information, where x represents the total number of people who ddownloaded songs from the site that month: x = 0.6x + 384 how many people who downloaded songs from the site that month downloaded q sam's latest single?

Fanny mendelssohn manages all the magazines and paperback books at a local grocery store. she prices many paperbacks to sell at $7.99. the cost to the store is $5.29. what is the markup rate on a paperback book, based on its cost?

Add: (6x^2-5x+3) + (3x^3+7x-8) a. 9x^2+12x-5 b. 9x^2+2x+11 c. 9x^2+2x-5 d. 9x^2-2x+5