若aa":bb"=1:2.且正方形abcd的面积为s
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a²+b²+c²-ab-bc-ac=0两边乘22a²+2b²+2c²-2ab-2bc-2ac=0(a²-2ab+b²)+
longtimenosee(C)因为AB了这么就都没C出来
因为AA'//BB'//CC',且AA'=BB'=CC'所以得3个平行四边形所以AB‖A'B'CB‖C'B'因为AB与CB,A'B'与C'B'分别交于点B,B',且分别属于面ABC和面A‘B’C‘所以
a=4,b=3,a-b=1
a²b²+2ab+1+a²+2ab+b²=0(ab+1)²+(a+b)²=0∴ab=-1a+b=0∴a²=b²=1∴a&
aa*bb+aa+bb+1=4aba²b²-2ab+1+a²+b²-2ab=0(ab-1)²+(a-b)²=0ab-1=0a-b=0a=b=
(b+2)-bb+2a=42a+2b=4a+b=2aa+2ab+bb-1=(a+b)^2-1=4-1=3
aa+bb=(a+b)(a+b)-2ab=9-2=7
∵ab=1,a≠1,∴M=aa+1+bb+1=aa+a b+bb+a b=aa (1+b )+bb ( 1+a )=1a+1+1b
∵P=a(b+1)+b(a+1)(a+1)(b+1)=2ab+a+bab+a+b+1,把ab=1代入得:2+a+b2+a+b=1;Q=b+1+a+1(a+1)(b+1)=a+b+2ab+a+b+1,把
a=2b=-3答案就得8+1/9=73/8
a^2+ab+b^2=1(a+b)^2=a^2+2ab+b^2=a^2+ab+b^2+ab=1+ab>=0ab>=-1(a-b)^2=a^2-2ab+b^2=a^2+ab+b^2-3ab=1-3ab>
(aa-bb)(aa-bb)-8(aa+bb)=(a+b)²(a-b)²-8a²-8b²=2²(a-b)²-8a²-8b²
令x=aa+bb则x(x-3)-4=0x²-3x-4=0(x+1)(x-4)=0因为x=aa+bb≥0所以aa+bb=4
88×88=774444×77=3388
∵a/b=2∴a=2b∴(a²-ab+b²)/(a²+b²)=(4b²-2b²+b²)/(4b²+b²)=3b
又已知aa-a=aa-b-5则a-b=5原式=0.5(a-b)(a-b)=12.5
∵abc=1,∴aab+a+1+bbc+b+1+cca+c+1=abcabbc+abc+bc+bbc+b+1+abccaab+abc+ca=1bc+b+1+bbc+b+1+1a+1+ab=1bc+b+
∵AA′∥BB′,AA′=BB′,∴四边形AA'B'B为平行四边形,∵BB′∥CC′,BB′=CC′,∴四边形B'BCC'为平行四边形∴AB=A'B',BC=B'C',AA'∥CC',且AA'=CC'