1. Tinh nhanh :
a) 54 x 11
b) 54 x 101
c) 675 x 1001
giup mik nhanh nhe
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a) 125.3+125.125.6
=125.3+125.750
=125.(3+750)
=125.753
=94125
b) (245.99+245)-(145.101-145)
=(245.(99+1))-(145.(101-1))
=245.100-145.100
=(245-145).100
=100.100
=10000
c) 154.(28+52)-45.(26+54)
=154.80-45.80
=(154-45).80
=109.80
=8720
a) 125x3+125+125x6
=125x(3+1+6)
=125x10
=1250
b) (245x99+245)-(145x101-145)
=(245x99+245)-(145x100)
=(245x100)-14500
=24500-14500
10000
c) 154x80-45x80
=80x(145-45)
=80x100
=8000
a,[120-12*5]:6
=[120-60]:6
=60:6
=10
b,494-[75+35:5]*2
=494-[75+7]*2
=494-82*2
=494-164
=330
c,1/4+[3/4:1/2]*5/6
=1/4+3/2*5/6
=1/4+5/4
=3/3
d,[360-15*6]:5
=[360-90]:5
=270:5
=54
a) (120-12*5):6= (120-60):6=60:6=10
b) 494-(75+35:5)*2= 494-(75+7)*2=494-82*2=494-164=330
c)1/4+(3/4:1/2)*5/6=1/4+3/2*5/6=1/4+5/4=6/4=3/2
d)(360-15*6):5=(360-90):5=270:5=54
a) 40 - x = 54
x = 40 - 54
x = -14
b) 36 - x = -11
x = 36 - (-11)
x = 47
c) 2.x - 3 = -14
2x = -14 + 3
2x = -11
x = -11/2
Có A = 1998 x 2002
= (2000 - 2) x (2000 + 2)
= 20002 - 22
= 20002 - 4
Mà B = 2000 x 2000 = 20002 ; 20002 - 4 < 20002
=> A < B
Có B = 35 x 53 - 18
= (34 + 1) x 53 - 18
= 34 x 53 + 53 - 18
= 34 x 53 + 35
=> B = D
a) \(\left(x+3\right)^2=x^2+6x+9\)
b) \(\left(2x+1\right)^2-\left(2x+3\right)\left(2x-3\right)=4x^2+4x+1-4x^2+9\)
\(=4x+10\)
a, 568 + 568 x 135 - 568 x 36
= 568 x ( 1 + 135 - 36)
= 568 x 100
56 800
b, 17 x 49 + 49 x 37 + 54 x 26 + 54 x 25
= 49 x ( 17 + 37) + 54 x ( 26 + 25 )
= 49 x 54 + 54 x 51
= 54 x ( 49 + 51)
= 54 x 100
= 5 400
c, 14 x 35 x 5 + 10 x 25 x 7 + 20 x 70
= ( 2 x 35) x ( 7 x 5) + ( 10 x 7) x 25 + 20 x 70
= 70 x 35 + 70 x 25 + 20 x 70
= 70 x ( 35 + 25 + 20)
= 70 x 80
= 5 600
a) 568 + 568 x 135 - 568 x 36
= 568 x ( 1+1+135-1-36 )
=568 x 100
=5680
b) 17 x 49 + 49 x 37 + 54 x 26 + 54 x 25
= 49 x ( 17 + 37 ) + 54 x ( 26 + 25 )
= 49 x 54 + 54 x 51
= 54 x ( 49 + 51 )
= 54 x 100
= 5400
c) 14 x 35 x 5 + 10 x 25 x 7 + 20 x 70
= 70 x 35 + 10 x 25 x 7+ 20 x 70
= 70 x 35 + 250 x 7 + 20 x 70
= 70 x 35 + 70 x 25 + 20 x 70
= 70 x (35+25+20)
= 70 x 80
= 5600
a) => \(\left(\frac{1}{3}-\frac{5}{6}x\right)^3=\frac{5}{6}-\frac{21}{54}=\frac{24}{54}=\frac{4}{9}\)
=> \(\frac{1}{3}-\frac{5}{6}x=\sqrt[3]{\frac{4}{9}}\) => \(\frac{5}{6}x=\frac{1}{3}-\sqrt[3]{\frac{4}{9}}\) => \(x=\frac{6}{5}.\left(\frac{1}{3}-\sqrt[3]{\frac{4}{9}}\right)\)
b) \(\frac{1}{3}\left(\frac{1}{2}x-1\right)^4=\frac{1}{12}-\frac{1}{16}=\frac{1}{48}\) => \(\left(\frac{1}{2}x-1\right)^4=\frac{3}{48}=\frac{1}{16}\)
=> \(\frac{1}{2}x-1=\frac{1}{2}\) hoặc \(\frac{1}{2}x-1=-\frac{1}{2}\)
=> \(\frac{1}{2}x=\frac{3}{2}\) hoặc \(\frac{1}{2}x=\frac{1}{2}\) => x = 3 hoặc x = 1
c) \(\left(1+5\right).\left(\frac{3}{5}\right)^{x-1}=\frac{54}{25}\) => \(\left(\frac{3}{5}\right)^{x-1}=\frac{9}{25}=\left(\frac{3}{5}\right)^2\)
=> x - 1= 2 => x = 3
d) \(\left(1+\left(\frac{2}{3}\right)^2\right).\left(\frac{2}{3}\right)^x=\frac{101}{243}\) => \(\frac{13}{9}.\left(\frac{2}{3}\right)^x=\frac{101}{243}\)
=> \(\left(\frac{2}{3}\right)^x=\frac{101}{243}:\frac{13}{9}=\frac{101}{351}\) (có lẽ đề sai)
2) \(\frac{1}{27^{11}}=\frac{1}{\left(3^3\right)^{11}}=\frac{1}{3^{33}}\); \(\frac{1}{81^8}=\frac{1}{\left(3^4\right)^8}=\frac{1}{3^{32}}\)
Vì 333 > 332 => \(\frac{1}{3^{33}}\) < \(\frac{1}{3^{32}}\) => \(\frac{1}{27^{11}}\) < \(\frac{1}{81^8}\)
b) \(\frac{1}{3^{99}}=\frac{1}{\left(3^3\right)^{33}}=\frac{1}{27^{33}}<\frac{1}{11^{21}}\) Vì 2733 > 1133 > 1121
Tinh nhanh :
a) 54 x 11 =594
b) 54 x 101 =5454
c) 675 x 1001 =675675
a) 54 x 11 =594
b) 54 x 101 =5454
c) 675 x 1001=675675
tks cho mk nhe