先因式分解 然后计算求值9x2 12xy
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是找规律的题1/2+1/4=3/4=(2的2次方-1)/(2的2次方)1/2+1/4+1/8=7/8=(2的3次方-1)/(2的3次方)1/2+1/4+1/8+1/16=15/16=(2的4次方-1)
8x³-16x²+8x-8xy²=8x[(x²-2x+1)-y²]=8x[(x-1)²-y²]=8x(x+y-1)(x-y-1)
1.2^2=1.4412^2=144120^2=144000.12^2=0.01440.012^2=0.000144①若2.42^2=5.8564,求24.2^2=585.64②若1.23^2=1.5
3*9*27*81*243*729=3*3²*3³*3^4*3^5*3^6=3^21
255*28=验算:28*255就是这样--------------再问:167*1549*327再答:都一样的只不过反着就行了167*15照那个竖式县城15*167
解题思路:因式分解解题过程:最终答案:略
(1).1.(x+18)^2=(22+18)^2=16002.(2a-b)^2=(2*1/2-5/4)^2=1/16(2).(2x-3)^2=0x=3/2(3).xy(a-b)^2=5*6^2=180
66X21+19X21+85X19=21(66+19)+85X19=21X85+85X19=85(21+19)=85X40=3600
解题思路:利用公式解答解题过程:varSWOC={};SWOC.tip=false;try{SWOCX2.OpenFile("http://dayi.prcedu.com/include/readq.
1999×1999+1999+2000=1999×(1999+1)+2000=1999×2000+2000=(1999+1)×2000=2000×2000=4000000.9³-9²
原式=2x(a-2)+y(a-2)=(a-2)(2x+y),当a=0.5,x=1.5,y=-2时,原式=(0.5-2)×(3-2)=-1.5.
x-2分之根号x-2除以x^3-2x^2分之根号x等于x乘以根号x^2-2x当x=4时,原式等于8根号2
=1/2-1/100=49/100
66X21+19X21+85X19=21*(66+19)+85*19=85*(21+19)=3400
9x的二次方+12xy+4y的二次方=(3x+2y)^2=[3*4/3+2*(-1/2)]^2=(4-1)^2=9
1.(X+Y)(X+Y+2XY)+(XY+1)XY-1)2.X^2-Y^2-2X-4Y-33.(XY-1)^2+(X+Y-2)(X+Y-2XY)4.X^4(Y^2-Z^2)+Y^4(Z^2-X^2)+
原式=3x(x²-2xy+y²)=3x(x-y)²=3×5/6×(5/6+1/6)²=5/2
5x(2x+1)-(2x+3)(5x-1)=10X^2+5X-10X^2-13X+3=-8X+3=-8×13+3=-101
5x(2x+1)-(2x+3)(5x-1)=10X^2+5X-10X^2-13X+3=-8X+3=-8×13+3=-101