已知2a-b=3,求代数式3(a²+3/2a-2b+1)-1/2(6a²-3a-6b-2)的值

已知2a-b=3,求代数式3(a²+3/2a-2b+1)-1/2(6a²-3a-6b-2)的值
已知2a-b=3,求代数式3(a²+3/2a-2b+1)-1/2(6a²-3a-6b-2)的值

已知2a-b=3,求代数式3(a²+3/2a-2b+1)-1/2(6a²-3a-6b-2)的值
解
3(a²+3/2a-2b+1)-1/2(6a²-3a-6b-2)
=(3a²-3a²)+(9/2a+3/2a)+(-6b+3b)+(3+1)
=6a-3b+4
=3(2a-b)+4
=3×3+4
=13

3/2a是3/(2a)还是(3/2)*a?