\(47.53=\left(50-3\right)\left(50+3\right)\)

\(=50^2-3^2\)

\(=2500-9\)

\(=2491\)

47 . 53

= (50 - 3) (50+3)

= 50² - 3²

Thuộc hằng đẳng thức là sẽ làm được

Hok tốt

\(47.53=\left(50-3\right)\left(50+3\right)\)

                \(=50^2-3^2\)

                  \(=2500-9=2491\)

B=(200-1)²=200²-2.200+1=40000-400+1=39601

B = (200 - 1)² = 200² - 400 + 1 = 39601

A = (100+1)² = 100² + 200 + 1 = 10201

=101.101=100.101+101=10100+101=10201

`1)(a^[1/4]-b^[1/4])(a^[1/4]+b^[1/4])(a^[1/2]+b^[1/2])`

`=[(a^[1/4])^2-(b^[1/4])^2](a^[1/2]+b^[1/2])`

`=(a^[1/2]-b^[1/2])(a^[1/2]+b^[1/2])`

`=a-b`

`2)(a^[1/3]-b^[2/3])(a^[2/3]+a^[1/3]b^[2/3]+b^[4/3])`

`=(a^[1/3]-b^[2/3])[(a^[1/3])^2+a^[1/3]b^[2/3]+(b^[2/3])^2]`

`=(a^[1/3])^3-(b^[2/3])^3`

`=a-b^2`

cau 1 \(x^2+6xy+9y^2=\left(x+3y\right)^2\)( binh phuong cua mot tong)

         \(x^2-10xy+25y^2=\left(x-5y\right)^2\)( binh phuong cua mot hieu ) 

\(=\left(3x\right)^2-2\cdot3x\cdot4+4^2-1\)

\(=\left(3x-4\right)^2-1^2\)

\(=\left(3x-4-1\right)\left(3x-4+1\right)\)

\(=\left(3x-5\right)\left(3x-3\right)\)

54*56=(55-1)(55+1)=55^2-1=3024

\(205^2-95^2=\left(205-95\right)\left(205+95\right)=110.300=33000\)

Không bít xin lỗi nhiều

20565-9562=        11003

D = 34² + 2.34.66 + 66² = (34 + 66)² = 100² = 10000

^_^