solve using the substitution and elimination method 3a-12b=9 4a-5b=3 can someone please help?

3a-12b=9 => a = 4b + 3; but, 4a-5b=3 => 4(4b + 3) -5b = 3 => 11b = -9 => b = -9/11 => a = -36/11 + 3 = -3/11;