To solve this system of equations by elimination, what operation could be used to eliminate the y-variable and find the value of x? 2x - 4y = 6 --3x + 3y = 12 A) add 3 times the second equation to 4 times the first equation B) add 4 times the second equation to 3 times the first equation C CO subtract 3 times the second equation from 4 times the first equation D) subtract 4 times the second equation from 3 times the first equation​