25×3/4-(-25)×1/2+25×(-1/4)怎么解?
一定要过程。
25×3/4-(-25)×1/2+25×(-1/4)
=25X3/4+25X1/2-25X1/4
=25X(3/4+1/2-1/4)
=25X1
=25
原式=3/4*25+1/2*25-1/4*25
=(3/4-1/4+1/2)*25
=1*25