有理数简便计算乘法1.(-3/4)x(8-1 1/3-0.04)2.49 15/16 x (-8)3.(-370)x(-1/4)+0.25 x 24.5 + (-5 1/2)x(-2590)
问题描述:
有理数简便计算乘法
1.(-3/4)x(8-1 1/3-0.04)
2.49 15/16 x (-8)
3.(-370)x(-1/4)+0.25 x 24.5 + (-5 1/2)x(-2590)
答
原式=(x^4-2x³+x²)+(5x³-10x²+5x)+(7x²-14x+7)
=x²(x²-2x+1)+5x(x²-2x+1)+7(x²-2x+1)
=(x²-2x+1)(x²+5x+7)
=(x-1)²(x²+5x+7)
答
1.(-3/4)x(8-1 1/3-0.04)=(-3/4)x(8-4/3-0.04)=(-3/4)x8-(-3/4)x4/3-(-3/4)x0.04=-6+1+0.03=-4.972.49 15/16 x (-8)=49x (-8)+15/16x (-8)=-392-15/2=-399-1/2=-399 1/23.(-370)x(-1/4)+0.25 ...