Question: Matrix and Equation Help

I created three different matrices which are A,B and C. I tried to calculate 4(AB)C but when I command it,it gives me an error. Does anyone know how can I do that?

I also need to create a system of three different linear equations with unknown that has one solution. My equations are 2x+3y=8 -x+2y=3 and 3x-4y=-5.Can anyone tell me how can I plot these lines, solve the system by using solve command and how can I solve the system using by matrices and row operations?

Please Wait...