Respuesta :

3x +4y =12

2x = y-6 Rewrite this as y = 2x+6

 now replace that for y in the first equation

3x + 4(2x+6) = 12

now do all the calculations:

3x + 8x +24 =12

11x + 24 = 12

11x = -12

x = -12/11 = -1 1/11

 now substitute -12/11 for x in the 2nd equation and solve

y = 2x+6

y = 2(-1 1/11) +6

y = 42/11 = 3 9/11