How do you solve this system by elimination?

-3x+4y=12
2x+y=-8

i dont know how to solve it.

James wants to promote his band on the internet. site a offers website hosting for $4.95 per month with a $49.95 startup fee. site b offers website hosting for $9.95 per month with no startup fee. for how many months would james need to keep the website for site a to be a better choice than site b? 1. define a variable for the situation. 2. write an inequality that represents the situation. 3.solve the inequality to find out how many months he needs to keep the website for site a to be less expensive than site b. 4. using words, describe how many months he needs to keep the website for site a to be less expensive than site b.

Angela is buying a dress that is on sale for 20% off. if the original price of the dress is $40.00, how much money is angela saving on the dress? a. $0.80 b. $3.20 c. $32.00 d. $8.00

The lengths of all sides of a triangle are integers when measured in decimeters. one of the sides has length of 1 dm and another of 3 dm. find the perimeter of the triangle.'