Question

初一的计算和因式分解帮帮忙5题

计算
（-2003)×2÷1/2+(-1/3)^-2÷2^-3 2011^2-2010*2012
因式分解
4X^2-64 -X^2+2X^2-X
化简
(3X+2)(3X-2)-5X(X-1)-(2X-1)^2

Answer 1

(-2003)×2÷(1/2) + (-1/3)^(-2)÷2^(-3)
= -2003×2×2 + [(-3)^2]×(2^3)
= -8012 + 9×8
= -7940

2011^2 - 2010×2012
= 2011^2 - (2011-1)×(2011+1)
= 2011^2 - (2011^2 -1)
= 1

4X^2-64
= 4(X^2 - 16)
= 4(X^2 - 4^2)
= 4(X+4)(X-4)

因式分解的第二题第一项是3次方还是2次方，下面两种分别给出：
-X^3+2X^2-X
= -X(X^2-2X+1)
= -X(X-1)^2

-X^2+2X^2-X
= X^2-X
= X(X-1)

(3X+2)(3X-2)-5X(X-1)-(2X-1)^2
= (3X)^2 - 2^2 - 5X^2 + 5X - [(2X)^2 - 2(2X) + 1]
= 9X^2 - 4 -5X^2 + 5X -4X^2 + 4X - 1
= 9X-5

Answer 2

计算: -7940 1
因式分解:4(X+4)(X-4) X(X-1)
化简;9X-5