What are large groups of similar eco-systems are called?

To solve this system of equations by elimination, what operation could be used to eliminate the y-variable and find the value of x? 6x + 5y = 2 4x + 2y = 8 a) subtract 2 times the second equation from 3 times the first equation b) subtract 3 times the second equation from 2 times the first equation c) subtract 5 times the second equation from 2 times the first equation d) subtract 2 times the second equation from 5 times the first equation