第1个回答 2012-03-05
1(-4x+3y)(-3y-4x)=(-4x+3y)(-4x-3y)=(-4x)^2-(3y)^2=16x^2-9y^2
所以16x^2-9y^2-M=16x^2+27y^2-5xy
M=(16x^2-9y^2)-(16x^2+27y^2-5xy)=-36y^2+5xy
2 (96^2)*(998^2)*(101^2)+(99^2) = 93 636 742 395 465
3 (a-2b)^2-2*(a+2b)*(a-2b)+(a+2b)^2
=[(a-2b)-(a+2b)]^2
=(-4b)^2
=16b^2
=16*4=64
e^(x^2+x)<=(1/e^2)^(x-2)=e^(4-2x),
∴x^2+x<=4-2x,
x^2+3x-4<=0,
-4<=x<=1.
1/16<=2^x<=2.
y=4^(x-1/2)]-3*2^x+5
=(1/2)(2^x)^2-3*2^x+5
=(1/2)(2^x-3)^2+1/2,↓,
y的值域为[1,2465/512
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