6.3*2012+56*201.2-1.9*2012
=6.3*2012+5.6*2012-1.9*2012
=2012*(6.3+5.6-1.9)
=2012*10
=20120
6.48*26+64.8*17.4-6.48*200
=6.48*26+6.48*174-6.48*200
=6.48*(26+174-200)
=6.48*0
=0
3X^2-5X+1=4
3X^2-5X=3
所以-12X^2+20X
=-4(3X^2-5X)
=-4*3
=-12
6.3*2012+56*201.2-1.9*2012
=6.3*2012+5.6*2012-1.9*2012
=2012*(6.3+5.6-1.9)
=2012*10
=20120
6.48*26+64.8*17.4-6.48*200
=6.48*26+6.48*174-6.48*200
=6.48*(26+174-200)
=6.48*0
=0
3X^2-5X+1=4
3X^2-5X=3
所以-12X^2+20X
=-4(3X^2-5X)
=-4*3
=-12