第三周周側(cè)
1.下列各式中,相等關(guān)系一定成立的是( )
A.(x-y)2=(y-x)2 B.(x+6)(x-6)=x2-6
C.(x+y)2=x2+y2 D.6(x-2)+x(2-x)=(x-2)(x-6)
2.下列運(yùn)算正確的是( )
A.x2+x2=2x4 B.a2•a3= a5
C.(-2x2)4=16x6 D.(x+3y)(x-3y)=x2-3y2
3.下列計(jì)算正確的是( )
A.(-4x)•(2x2+3x-1)=-8x3-12x2-4x B.(x+y)(x2+y2)=x3+y3
C.(-4a-1)(4a-1)=1-16a2 D.(x-2y)2=x2-2xy+4y2
4.(x+2)(x-2)(x2+4)的計(jì)算結(jié)果是( )
A.x4+16 B.-x4-16 C.x4-16 D.16-x4
5.19922-1991×1993的計(jì)算結(jié)果是( )
A.1 B.-1 C.2 D.-2
6.對(duì)于任意的整數(shù)n,能整除代數(shù)式(n+3)(n-3)-(n+2)(n-2)的整數(shù)是( )
A.4 B.3 C.5 D.2
7.( )(5a+1)=1-25a2,(2x-3) =4x2-9,(-2a2-5b)( )=4a4-25b2
8.99×101=( )( )= .
9.(x-y+z)(-x+y+z)=[z+( )][ ]=z2-( )2.
10.多項(xiàng)式x2+kx+25是另一個(gè)多項(xiàng)式的平方,則k= .
11.(a+b)2=(a-b)2+ ,a2+b2=[(a+b)2+(a-b)2]( ),
a2+b2=(a+b)2+ ,a2+b2=(a-b)2+ .
12.計(jì)算.(1)(a+b)2-(a-b)2；
(2)(3x-4y)2-(3x+y)2；
(3)(2x+3y)2-(4x-9y)(4x+9y)+(2x-3y)2；
(4)1.23452+0.76552+2.469×0.7655；
(5)(x+2y)(x-y)-(x+y)2.
13.已知m2+n2-6m+10n+34=0,求m+n的值
14.如果(2a+2b+1)(2a+2b-1)=63,求a+b的值.
15.已知(a+b)2=60,(a-b)2=80,求a2+b2及ab的值.