Question 109394
First calculate 3A


{{{3A=3(matrix(2,2,2,-1,3,0))=(matrix(2,2,2*3,-1*3,3*3,0*3))=(matrix(2,2,6,-3,9,0))}}}



Now subtract B from 3A


{{{3A-B=(matrix(2,2,6,-3,9,0))-(matrix(2,2,4,-2,5,1))=(matrix(2,2,6-4,-3--2,9-5,0-1))=(matrix(2,2,2,-1,4,-1))}}}



So {{{3A-B=(matrix(2,2,2,-1,4,-1))}}}