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nhiều lắm nhớ sao được có hơn 20 cái hằng đẳng thức mà tự tra google đi
\(7,=\left(\sqrt{x}\right)^2+2\cdot2\sqrt{x}+2^2=\left(\sqrt{x}+2\right)^2\\ 8,=\left(\sqrt{x}\right)^2-2\cdot3\sqrt{x}+3^2=x-6\sqrt{x}+9\\ 9,=\sqrt{x^3}+\sqrt{y^3}=\left(\sqrt{x}+\sqrt{y}\right)\left(x-\sqrt{xy}+y\right)\\ 10,=\sqrt{x^3}-\sqrt{y^3}=\left(\sqrt{x}-\sqrt{y}\right)\left(x+\sqrt{xy}+y\right)\\ 11,=\sqrt{x^3}+1^3=\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)\\ 12,=\sqrt{x^3}-2^3=\left(\sqrt{x}-2\right)\left(x+2\sqrt{x}+4\right)\)
7: \(x+4\sqrt{x}+4=\left(\sqrt{x}+2\right)^2\)
8: \(\left(\sqrt{x}-3\right)^2=x-6\sqrt{x}+9\)
9: \(x\sqrt{x}+y\sqrt{y}=\left(\sqrt{x}+\sqrt{y}\right)\left(x-\sqrt{xy}+y\right)\)
7) \(x+4\sqrt{x}+4=\left(\sqrt{x}\right)^2+2\sqrt{x}.2+2^2=\left(\sqrt{x}+2\right)^2\)
8) \(\left(\sqrt{x}-3\right)^2=\left(\sqrt{x}\right)^2-2.\sqrt{x}.3+3^2=x-6\sqrt{x}+9\)
9) \(x\sqrt{x}+y\sqrt{y}=\sqrt{x^3}+\sqrt{y^3}=\left(\sqrt{x}+\sqrt{y}\right)\left(x-\sqrt{xy}+y\right)\)
10) \(x\sqrt{x}-y\sqrt{y}=\sqrt{x^3}-\sqrt{y^3}=\left(\sqrt{x}-\sqrt{y}\right)\left(x+\sqrt{xy}+y\right)\)
11) \(x\sqrt{x}+1=\sqrt{x^3}+1^3=\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)\)
12) \(x\sqrt{x}-8=\sqrt{x^3}-2^3=\left(\sqrt{x}-2\right)\left(x+2\sqrt{x}+4\right)\)
9) \(x-1=\left(\sqrt{x}\right)^2-1=\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)\)
10) \(x\sqrt{x}-1=\sqrt{x^3}-1=\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)\)
11) \(x-2\sqrt{x}-63=\left(x-2\sqrt{x}+1\right)-64=\left(\sqrt{x}-1\right)^2-8^2=\left(\sqrt{x}-1-8\right)\left(\sqrt{x}-1+8\right)=\left(\sqrt{x}-9\right)\left(\sqrt{x}+7\right)\)
Biến đổi các đa thức mà trong này không có đa thức sao mà chuyển
\(a,19^2=\left(18+1\right)^2=18^2+2.18.1+1^2=324+36+1=361\)
\(28^2=\left(27+1\right)^2=27^2+2.27.1+1^2=729+54+1=784\)
\(81^2=\left(80+1\right)^2=80^2+2.80.1+1^2=6400+160+1=6561\)
\(91^2=\left(90+1\right)^2=90^2+2.90.1+1^2=8100+180+1=8281\)
\(b,19.21=\left(20-1\right)\left(20+1\right)=20^2-1^2=400-1=399\)
\(29.31=\left(30-1\right)\left(30+1\right)=30^2-1^2=900-1=899\)
\(39.41=\left(40-1\right)\left(40+1\right)=40^2-1^2=1600-1=1599\)
\(c,28^2-8^2=\left(28-8\right)\left(28+8\right)=20.36=720\)
\(56^2-46^2=\left(56-46\right)\left(56+46\right)=10.102=1020\)
\(67^2-57^2=\left(67-57\right)\left(67+57\right)=10.124=1240\)
1. (a + b)2 = a + 2ab + b2
2. (a - b)2 = a2 - 2ab +b2
3. a2 + b2 = (a + b) - 2ab = (a - b) + 2ab
4. a - b = (a + b)(a - b)
chi nho 4 cai do thui bn co gi hoi mk co hinh anh ban hay dua mail cho mk nhe mk cho bn 13 hang dang thuc luon
xl em ko biết
because em ms lớp 1