www.gsyw.net > 当A=2,B=0.8时,求值2(A%B)=( )

当A=2,B=0.8时,求值2(A%B)=( )

当a=2,b=0.8时,求值2(a-b)=( 2.4)

(3a^2b-2ab)-(ab-4a^2)+(3ab-a^2b)=3a^2b-2ab-ab+4a^2+3ab-a^2b=3a^2b-2ab-ab+4a^2+3ab-a^2b=3a^2b+4a^2-a^2b-2ab-ab+3ab=3a^2b+4a^2-a^2b=6a^2b这样a无论得-2或2,6a^2b=6(+-2)^2b=24b所以计算结果是对的

4a-(2b-a)=4a-2b^2+a=5a-2b^2因为a=0.8,b=0.5所以原式=5*0.8-2*0.5^2=4-0.5=3.5

A=1/2,B=2A=1,原式=4AB=4*1/2*1=2

原式为 2(a+b)(a-b)-(a+b)^2+(a-b)^2 =(a-b)^2+2(a+b)(a-b)+(a+b)^2-2(a+b)^2 =(a-b+a+b)^2-2(a+b)^2 =4a^2-2(a+b)^2=16-25/2

原式=3ab-2ab-ab+4a+3ab-ab=2ab+4a∵(-a)=a∴2(-a)b+4(-a)=2ab+4a

原式=[(A-B)+4AB]/(A-B)*[(A+B)-4AB]/(A+B)=(A-2AB+B+4AB)/(A-B)*(A+2AB+B-4AB)/(A+B)=(A+2AB+B)/(A-B)*(A-2AB+B)/(A+B)=(A+B)/(A-B)*(A-B)/(A+B)=(A+B)(A-B)=(2+√2+2-√2)(2+√2-2+√2)=8√2

=1-1/6*(9-8)=5/6

解:(合并同类项) 6a+2.5b-a+1.5 =5a+2.5b+1.5 当a=1.5,b=2时 5a+2.5b+1.5 =5*1.5+2.5*2+1.5 =7.5+5+1.5 =14

把(a-b)和(a+b)看作整体,利用平方差公式化简后,再把a,b的值代入化简后的代数式求值.解答:解:(a-b)2-(a+b)2,=(a-b+a+b)(a-b-a-b),=2a*(-2b),=-4ab,当a=3,b=-2时,原式=-4*3*(-2)=24.

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