我要20道化简求值初一的题目,急,答:1,3x'y-[2x'y-(2xyz-x'z)-4x'z]-xyz,其中x=-2,y=-3,z=1,原式=3x'y-[2x'y-(2xyz-x'z)-4x'z]-xyz =3x'y-2x'y+2xyz-x'z+4x'z-xyz =x'y-xyz+3x'z 当x=2,y=3,z=1时 原式=4*(-3)-2*3*1+3*4*1 =-12-6+12 =-6 2,3X+2Y)+(4X+3Y)其中X=5,Y...
初二上化简求值题100道,要现成的,多就发答:21.已知A=x3-2x2+x-4,B=2x3-5x+3,计算A+B=___. 22.已知A=x3-2x2+x-4,B=2x3-5x+3,计算A-B=___. 23.若a=-0.2,b=0.5,代数式-...(四)将下列各式先化简,再求值 97.已知a+b=2,a-b=-1,求3(a+b)2(a-b)2-5(a+b)2×(a-b)2的值. 98.已知A=a2+2b2-3c2,B=-b2-2c2...