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a) 1012=(100+1)2=1002+2.50.2+12=10000+200+1=10201
b)1992=(200-1)2=2002 -2.200.1+12=40000-400+1=39601
c) 47.53=(50-3)(50+3)=502-32=2500-9=2491
a) 1012 =(100+1)2 =10000+1=10001
b) 1992 =(199+1)2 =2002 =40000
c) 47.53=(40+7 .50+3)=20000+10=20010
a)Ta có \(101^2\)=\(\left(100+1\right)^2\)=10000+200+1
=10201
b)\(199^2\)=\(\left(200-1\right)^2=40000-400+1\)=39601
c)47.53=\(\left(50-3\right)\left(50+3\right)=50^2-3^2\)=2500-9=2491
d )
\(B=5\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)\left(2^{64}+1\right)\)
\(\Rightarrow B=\frac{5}{3}\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)\left(2^{64}+1\right)\)
\(\Rightarrow B=\frac{5}{3}\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)\left(2^{64}+1\right)\)
\(\Rightarrow B=\frac{5}{3}\left(5^8-1\right)\left(5^8+1\right)\left(5^{16}+1\right)\left(5^{32}+1\right)\left(5^{64}+1\right)\)
\(\Rightarrow B=\frac{5}{3}\left(2^{16}-1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)\left(2^{64}+1\right)\)
\(\Rightarrow B=\frac{5}{3}\left(2^{32}-1\right)\left(2^{32}+1\right)\left(2^{64}+1\right)\)
\(\Rightarrow B=\frac{5}{3}\left(2^{64}-1\right)\left(2^{64}+1\right)\)
\(\Rightarrow B=\frac{5}{3}\left(2^{128}-1\right)\)
Sửa lại dấu \(\Rightarrow\)dòng 3 :
\(B=\frac{5}{3}\left(2^8-1\right)\left(2^8+1\right)\left(2^{16}+1\right)\left(2^{32}+1\right)\left(2^{64}+1\right)\)
Bài 1
a,=10201 b,39601 c,2491
Bài 2
(2x+3y)^2 +2(3x+3y)+1=(2x+3y+1)^2
Bài `1.`
`a, 101^2=(100+1)^2=100^2 +2.100.1 +1^2=10201`
`b, 199^2=(200-1)^2=200^2 - 2 . 200.1 +1^2=39601`
`c, 47 . 53=(50 - 3)(50+3) = 50^2 - 3^2=2491`
Bài `2.`
`(2x+3y)^2 +2 (2x+3y) +1 = (2x+3y)^2 +2 . (2x+3y).1+1^2=(2x+3y+1)^2`
\(B=\left(\frac{1}{200^2}-1\right)\left(\frac{1}{199^2}-1\right)...\left(\frac{1}{101^2}-1\right)\)
\(=\left(\frac{1}{200}-1\right)\left(\frac{1}{200}+1\right)\left(\frac{1}{199}-1\right)\left(\frac{1}{99}-1\right)...\left(\frac{1}{101}-1\right)\left(\frac{1}{101}+1\right)\)
\(=\frac{-199}{200}.\frac{201}{200}.\frac{-198}{199}.\frac{200}{199}...\frac{-100}{101}.\frac{102}{101}\)
\(=\left(-\frac{199}{200}.\frac{-198}{199}...\frac{-100}{101}\right)\left(\frac{201}{200}.\frac{200}{199}...\frac{102}{101}\right)\)
\(=\frac{100}{200}.\frac{201}{101}=\frac{201}{202}\)
A= 1012 = 10201
B= 1092 = 11881
C= 342 + 662 + 68*66 = 342 + 2*34*66 + 662 = (34 + 36)2 =702 = 4900
D=742 + 242 - 48 *74 = 742 - 2*24 *74 + 242 = (74 - 24)2= 502 = 2500
Bài 1:
a) \(9x^2-6x+1\)
= \(\left(3x\right)^2\) - 2.3x.1 + 1
= \(\left(3x-1\right)^2\)
Bài 2:
\(\left(a-b\right)^2\)
= \(\left(a+b\right)^2-4ab\)
Thay a + b = 7 và a.b = 12 vào biểu thức
⇒ \(7^2\) - 4.12
= 49 - 48
= 1
Bài 3:
a) \(49x^2-70x+25\)
= \(\left(7x\right)^2\) - 2.7x.5 + \(5^2\)
= \(\left(7x+5\right)^2\)
Thay x = \(\frac{1}{7}\) vào biểu thức
⇒ \(\left(7.\frac{1}{7}+5\right)^2\)
= \(5^2\)
= 25
b) \(101^2\)
= \(\left(100+1\right)^2\)
= \(100^2+2.100.1+1\)
= 10000 + 200 + 1
= 10201
c) 47.53
= (50 - 3)(50 + 3)
= \(50^2-3^2\)
= 2500 - 9
= 2491
\(\left(6x+1\right)^2+\left(6x-1\right)^2-2\left(1+6x\right)\left(6x-1\right)=\left[\left(6x+1\right)-\left(6x-1\right)\right]^2=\left(6x+1-6x+1\right)^2=2^2=4\)
\(x\left(2x^2-3\right)-x^2\left(5x+1\right)+x^2=2x^3-3x-5x^3-x^2+x^2=-3x^3-3x\)
\(101^2=\left(100+1\right)^2=100^2+200+1=10000+201=10201\)
\(97\times103=\left(100-3\right)\left(100+3\right)=100^2-3^2=10000-9=9991\)
\(105-52=53\)
a) 1012 = (100 + 1)2 = 1002 + 2.100 + 1 = 10000 + 200 + 1 = 10201
b) 1992 = (200 – 1)2 = 2002 – 2.200 + 1 = 40000 – 400 + 1 = 39601
c) 47.53 = (50 – 3)(50 + 3) = 502 – 32 = 2500 – 9 = 2491.