All you do is distribute the -3 into 4x+3 and repeat the process with the 4 and 6x+1. When you finish distributing, you should have -12x-9+24x+4=43. Combine like terms. 12x-5=43. Add 5 to 43 to get 48. Divide by 12 to get x by itself and finally your answer should be x=4.