Question

Which of these steps will eliminate a variable in this system?

Answer 1

Answer:

option c is correct

Step-by-step explanation:

for any variable to be eliminated in a simultaneous equation, the one of the coefficients must be the same in the two equations. and:

FOR OPTION A

if the first equation is multiplied by 3 , we will be having 12x-27y= 24 as the new equation 1 and since the cofficient of y or x are different in equation 1 and 2, no variable can be eliminated.

FOR OPTION B

if the second equation is multiplied by 2, our new equation 2 will be 4x+6y= 48. here, the cofficient of x in the two equations are now the same but since we're going to add, 4x+4x = 8x which does not eliminate x

FOR OPTION C

if the second equation is multiplied by 2, our new equation 2 becomes 4x + 6y= 48 and if we subtract, 4X-4x= 0 so we have eliminated X ( option C is correct)

FOR OPTION D

if the second equation is multiplied by three, our new equation 2 becomes 6x+9y= 72 and subtracting,-9y -9y= -18y which does not eliminate y