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b) 73.9+ 32.74- 45.539
=343.9+9.2401-45.539
=9.(343+2401)-45.539
=9.2744-24355
=24696-24355
=341
a) 132- (116-(132-1282))
=132- ( 116-(132-16384))
=132-(116+16252)
=132-16368
=16236
a) 52x-3 -2.52 = 52.3
52x.125 = 52.3 + 2.52
52x.125 = 125
52x = 1 = 50
=> 2x = 0 => x =0
b) \(A=\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}+\frac{1}{90}+\frac{1}{110}+\frac{1}{132}\)
\(A=\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}+\frac{1}{9.10}+\frac{1}{10.11}+\frac{1}{11.12}\)
\(A=\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+...+\frac{1}{10}-\frac{1}{11}+\frac{1}{11}-\frac{1}{12}\)
A = 1/5 - 1/12
A = 7/60
\(132+[116-\left(132-128\right)^2]\)
\(=132+[116-4^2]\)
\(=132+[116-16]\)
\(=132+100\)
\(=232\)
A = 1/5.6 + 1/6.7 + ...... + 1/11.12
= 1/5 - 1/6 + 1/6 - 1/7 + ..... + 1/11 - 1/12
= 1/5 - 1/12
= 7/60
Có : 2B = 1+1/2+1/2^2+.....+1/2^2015
B = 2B - B = (1+1/2+1/2^2+.....+1/2^2015) - (1/2+1/2^2+.....+1/2^2016)
= 1 - 1/2^2016
Tk mk nha
\(A=\frac{1}{30}+\frac{1}{42}+\frac{1}{56}+\frac{1}{72}+\frac{1}{90}+\frac{1}{110}+\frac{1}{132}\)
\(=\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}+\frac{1}{9.20}+\frac{1}{10.11}+\frac{1}{11.12}\)
\(=\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}+\frac{1}{10}-\frac{1}{11}+\frac{1}{11}-\frac{1}{12}\)
\(=\frac{1}{5}-\frac{1}{12}=\frac{7}{60}\)
2)
a) 55 - ( 5 . 42 - 3. 52 )
= 55 - ( 5 . 16 - 3 . 25 )
= 55 - ( 80 - 75 )
= 55 - 5
= 50
b) ( 7 . 33 - 4 . 33 ) : 34
= ( 7 . 27 - 4 . 27 ) : 34
= [ 27 . ( 7 - 4 ) ] : 34
= [ 27 . 3 ] : 34
= 81 : 34
= 34 : 34
= 1
c) 100 : { 2 . [ 52 - ( 35 - 8 ) ] }
= 100 : { 2 . [ 52 - 27 ] }
= 100 : { 2 . 25 }
= 100 : 50
= 2
d) 2 + 4 + 6 + 8 + .... + 50
Ta có :
Số số hạng là : ( 50 - 2 ) : 2 + 1 = 25 ( số hạng )
Tổng là : ( 50 + 2 ) . 25 : 2 = 650
e) 132 . 79 + 132 . 19 + 264
= 132 . 79 + 132 . 19 + 132 . 2
= 132 . ( 79 + 19 + 2 )
= 132 . 100
= 13 200
f) 91 . 51 + 49 . 163 - 49 . 72
= 91 . 51 + 49 . ( 163 - 72 )
= 91 . 51 + 49 . 91
= 91 . ( 51 + 49 )
= 91 . 100
= 9100
1) 22.25.17.+5.20.27+102.56
=4.25.17+5.20.27+100.56
=100.17+100.27+100.56
=100(17+27+56)
=100.100
=10000
2) 132-[116-(132-1282)]
=132-[116-(132-16384)]
=132-[116-(-16252)]
=132-(116+16252)
=132-16368
=-16236
3) 4.52-81:32
=4.25-34:32
=100-34-2
=100-32
=100-9
=91
d) 135(-12 + 247) - 147(135 - 12)= -12.135 + 135.147 - 147.135 + 12.147 = (-12.135 + 12.147) + (135.147 - 147.135) = 12(-135 + 147) + 0 = -12.12 = -144
Bài 1:
a) [3.(-2) - (-8)].(-7) - (-2).(-5) = -7(-6 + 8) - 2.5= -7.2 - 2.5 = -2(7 + 5) = -2.12 = -24
132 - (236 - 432 - 576) = 132 - (-196 - 576) = 132 - (-772) = 904
55 - [132 - 2 x (45 - 42)2] + 7 = 55 - (132 - 2 x 32) + 7 = 55 - (132 - 2 x 9) + 7 = 55 - (132 - 18) + 7 = 55 - 114 + 7 = -52
Hoc tot!!!
132-(236-432-576)=132-236+432+576=-104+432+576=328+576=904
55-[132-2(45-42)2]+7
= 55-[132-2*32]+7
= 55-[132-2*9]+7
= 55-[132-18]+7
= 55-114+7=-52
(Chúc học tốt nha :) :) )