1:求(1/1/2)~n *(2/3)~n+1的值.(n≠0)2:(-2x+1)(2x-1)=( )A:-4x~2+4x-1B:4x~2-1C:-4x~2-1D:1-4x~23:正确的是( )A:(a-2)(a~2-2a+4)=a~3-8B:(2ab+1)(2ab-1)=2a~2b~2-1C:(x~2+2xy+y~2)~3=x~6+8x~3y~3+y~6D:(x-y)(x~2-2xy+y~2)=(x-y)~34:计算(1) 12a~4-3a[a~2-4a(a~3-2a~2+3a)] (2) 3(x~2-2)-5x(x+1)+4x(1-x)
热心网友
1:求(1/1/2)~n *(2/3)~n+1的值。(n≠0)看不清，是不是下面的？原式＝2^n *(2/3)^n +1 = (4/3)^n +12:(-2x+1)(2x-1)=(A)A:-4x~2+4x-1 ,B:4x~2-1 ,C:-4x~2-1 ,D:1-4x~2原式＝-(2x-1)^2 = -4x^2 +4x -13:正确的是(D)A:(a-2)(a~2-2a+4)=a~3-8 ,B:(2ab+1)(2ab-1)=2a~2b~2-1C:(x~2+2xy+y~2)~3=x~6+8x~3y~3+y~6 ,D:(x-y)(x~2-2xy+y~2)=(x-y)~34:计算(1) 12a~4-3a[a~2-4a(a~3-2a~2+3a)]原式＝12a^4-3a(a^2 -4a^4+8a^3 -12a^2)=12a^5 -12a^4 +33a^3(2) 3(x~2-2)-5x(x+1)+4x(1-x)原式＝3x^2-6-5x^2-5x+4x-4x^2 =-6x^2 -x -6。
热心网友
1:求(1/1/2)~n *(2/3)~n+1的值。(n≠0)看不清，是不是下面的？原式＝2^n *(2/3)^n +1 = (4/3)^n +12:(-2x+1)(2x-1)=(A)A:-4x~2+4x-1 ,B:4x~2-1 ,C:-4x~2-1 ,D:1-4x~2原式＝-(2x-1)^2 = -4x^2 +4x -13:正确的是(D)A:(a-2)(a~2-2a+4)=a~3-8 ,B:(2ab+1)(2ab-1)=2a~2b~2-1C:(x~2+2xy+y~2)~3=x~6+8x~3y~3+y~6 ,D:(x-y)(x~2-2xy+y~2)=(x-y)~34:计算(1) 12a~4-3a[a~2-4a(a~3-2a~2+3a)]原式＝12a^4-3a(a^2 -4a^4+8a^3 -12a^2)=12a^5 -12a^4 +33a^3(2) 3(x~2-2)-5x(x+1)+4x(1-x)原式＝3x^2-6-5x^2-5x+4x-4x^2 =-6x^2 -x -6。