1.5*8.4+3*3/10+15*10%
=1.5x8.4+3x0.3+15x0.1
=1.5x8.4+1.5x0.6+1.5x1
=1.5x(8.4+0.6+1)
=1.5x10
=15
如果本题有什么不明白可以追问,