Can someone explain how to do this problem? I got a different answer than my teacher...

3[5-2(x+1)]

I got 9x+9 and my teacher said it was 9-6x

2 answers

3[5-2(x+1)]

3 [5 - 2x - 2]
15 - 6x - 6
9 - 6x

I agree with your teacher.
3[5-(2x+1(2))]= 3[5-(2x+2)]
3[5-2x-2]= 3[3-2x]= 9-6x