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21 tháng 6 2016

15x6+20x3+25x14

=90+60+350

=500

15x6+20x3+25x14

=5x3x6+5x4x3+5x5x14

=5x(3x6+4x3+5x14)

=5x100

=500

21 tháng 6 2016

C1 :

15 x 6 + 20 x 3 + 25 x 14 

= 90 + 60 + 350

= 500

C2 :

15 x 6 + 20 x 3 + 25 x 14

= 5 x 3 x 6 + 5 x 4 x 3 + 5 x 5 x 14

= 5 x 18 + 5 x 12 + 5 x 70

= 5 x 100

= 500

21 tháng 6 2016

Cách 1:

=90+60+350=500

Cách 2:

=5x3x6+5x4x3+5x5x14=5x(3x6+4x3+5x14)=5x100=500

k mk nha bn

29 tháng 8 2016

a, 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3

= 2 x 12 x 31 + 4 x 6 x 42 + 8 x 3 x 27

= 24 x 31 + 24 x 42 + 24 x 27

= 24 x ( 31 + 24 + 27 )

= 24 x 82 

= 1968

b, 2 x 53 x 12 + 4 x 6 x 87 - 3 x 8 x 40

= 24 x 53 + 24 x 87 - 24 x 40

= 24 x ( 53 + 87 - 40 )

= 24 x 100

= 2400

c, Tương tự

1 tháng 9 2016

a) = 1968

b) = 2400

đó là kq câu a) ; b)

**** Nha bn

15*6*4*125*8=360000

14*25*6*7=14700

24*3*5*10=3600

18*26*25*9=105300

12*5*15*7=6300

20 tháng 9 2019

15 x 6 x 4 x 125 x 8
= (15 x 4) x (125 x 8) x 6
= 60 x 1000 x 6
= 60000 x 6
= 360000
14 x 25 x 6 x 7
= (14 x 25) x 6 x 7
= 350 x 6 x 7
= 2100 x 7
= 14700
24 x 3 x 5 x 10
= (24 x 5) x 10 x 3
=  120 x 10 x 3
= 1200 x 3
= 3600
18 x 26 x 25 x 9 
= (26 x 25) x 18 x 9
= 650 x 18 x 9
= 11700 x 9
= 105300
12 x 5 x 15 x 7
= (12 x 15) x 5 x 7
= 180 x 5 x 7
= 900 x 7
= 6300

25 tháng 11 2023

1) \(\left(+15\right)+\left(+17\right)=15+17=32\)

2) \(\left(-3\right)+\left(-7\right)=-3-7=-\left(3+7\right)=-10\)

3) \(\left(-25\right)+\left(+4\right)=-25+4=-\left(25-4\right)=-21\)

4) \(\left(-6\right)+\left(-54\right)=-6-54=-\left(6+54\right)=-60\)

5) \(\left(-15\right)+20=20-15=5\)

6) \(\left(-5\right)+8+7+5\)

\(=\left(-5+5\right)+\left(8+7\right)\)

\(=15\)

7) \(\left(-8\right)+\left(-11\right)+\left(-2\right)\)

\(=\left[\left(-8\right)+\left(-2\right)\right]+\left(-11\right)\)

\(=\left(-10\right)+\left(-11\right)\)

\(=-21\)

8) \(15+\left(-5\right)+\left(-14\right)+\left(-16\right)\)

\(=\left[15+\left(-5\right)\right]+\left[\left(-14\right)+\left(-16\right)\right]\)

\(=10+\left(-30\right)\)

\(=-20\)

9) \(\left(-20\right)+\left(-14\right)+3+\left(-86\right)\)

\(=\left[\left(-20\right)+3\right]+\left[\left(-14\right)+\left(-86\right)\right]\)

\(=\left(-17\right)+\left(-100\right)\)

\(=-117\)

10) \(\left(-136\right)+123+\left(-264\right)+\left(-83\right)+240\)

\(=\left[\left(-136\right)+\left(-264\right)\right]+\left[123+\left(-83\right)\right]+240\)

\(=\left(-400\right)+40+240\)

\(=\left(-360\right)+240\)

\(=-120\)

11) \(\left(-596\right)+2001+1999+\left(-404+189\right)\)

\(=\left(-596\right)+2001+1999-404+189\)

\(=\left[\left(-596\right)-404\right]+\left(2001+189\right)+1999\)

\(=\left(-1000\right)+2190+1999\)

\(=1190+1999\)

\(=3189\)

12) \(314+\left(-153\right)+64+121+\left(-247\right)+218\)

\(=\left(314+64+121\right)+\left[\left(-153\right)+\left(-247\right)\right]+218\)

\(=\left(378+121\right)+\left(-400\right)+218\)

\(=499-400+218\)

\(=99+218\)

\(=317\)

\(\text{#}Toru\)

\(a.13.\left(78+22\right)=13.100=1300\)

\(b.25.70+28.25+25.2=25.\left(70+28+2\right)=25.100=2500\)

\(c.\dfrac{15.3.14.2.19}{19.14.15}=6\)

\(d.\dfrac{132.70.60}{12.35.20}=\dfrac{11.12.35.2.20.3}{12.35.20}=66\)

10 tháng 7 2023

`1, -2/9 xx 15/17 + (-2/9) xx 2/17`

`= -2/9 xx (15/17 + 2/17)`

`= -2/9 xx 17/17`

`=-2/9xx1`

`=-2/9`

__

`-5/3 xx 6/5 + (-7/9) xx 3/10`

`= -30/15 + (-21/90)`

`= -2 + (-7/30)`

`=-60/30 +(-7/30)`

`=-67/30`

__

`15/20 xx 7/5 + (-9/7) xx (-6/4)`

`=3/4 xx7/5 + (-9/7) xx(-6/4)`

`= 21/20 + 54/28`

`= 21/20 + 27/14`

`=417/140`

__

`-25/13 xx 5/19 + (-25/13) xx 14/19`

`=-25/13 xx (5/19 +14/19)`

`=-25/13 xx 19/19`

`= -25/13 xx 1`

`=-25/13`

__

`-7/13 xx 13/5 + (-9/7) xx 5/3`

`=-7/5 +(-15/7)`

`=-124/35`

LM
Lê Minh Vũ
CTVHS VIP
3 tháng 10 2021

\(\left(27.700-45.20\right)\div\left(45-40+35-30+25-20+15-10+5\right)\)

\(=\)\(\left(27.100-45.20\right)\div25\)

\(=\)\(\left(27.35.20-45.20\right)\div25\)

\(=\)\(\left[\left(27.35-45\right).20\right]\div25\)

\(=\)\(18000\div25\)

\(=\)\(750\)

9 tháng 7 2023

c) \(\left(34-2x\right)\left(2x-6\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}34-2x=0\\2x-6-0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}2x=34\\2x=6\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=17\\x=3\end{matrix}\right.\)

d) \(\left(2019-x\right)\left(3x-12\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}2019-x=0\\3x-12=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=2019\\3x=12\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=2019\\x=4\end{matrix}\right.\)

e) \(57\left(9x-27\right)=0\)

\(\Rightarrow9x-27=0\)

\(\Rightarrow9\left(x-3\right)=0\)

\(\Rightarrow x-3=0\)

\(\Rightarrow x=3\)

f) \(25+\left(15-x\right)=30\)

\(\Rightarrow25+15-x=30\)

\(\Rightarrow40-x=30\)

\(\Rightarrow x=40-30\)

\(\Rightarrow x=10\)

g) \(43-\left(24-x\right)=20\)

\(\Rightarrow43-24+x=20\)

\(\Rightarrow19+x=20\)

\(\Rightarrow x=20-19\)

\(\Rightarrow x=1\)

h) \(2\left(x-5\right)-17=25\)

\(\Rightarrow2\left(x-5\right)=17+25\)

\(\Rightarrow x-5=21\)

\(\Rightarrow x=21+5\)

\(\Rightarrow x=26\)

i) \(3\left(x+7\right)-15=27\)

\(\Rightarrow3\left(x+7\right)=27+15\)

\(\Rightarrow x+7=14\)

\(\Rightarrow x=14-7\)

\(\Rightarrow x=7\)

j) \(15+4\left(x-2\right)=95\)

\(\Rightarrow4\left(x-2\right)=95-15\)

\(\Rightarrow4\left(x-2\right)=80\)

\(\Rightarrow x-2=20\)

\(\Rightarrow x=20+2\)

\(\Rightarrow x=22\)

k) \(20-\left(x+14\right)=5\)

\(\Rightarrow x+14=20-5\)

\(\Rightarrow x+14=15\)

\(\Rightarrow x=15-14\)

\(\Rightarrow x=1\)

l) \(14+3\left(5-x\right)=27\)

\(\Rightarrow3\left(5-x\right)=27-14\)

\(\Rightarrow3\left(5-x\right)=13\)

\(\Rightarrow5-x=\dfrac{13}{3}\)

\(\Rightarrow x=5-\dfrac{13}{3}\)

\(\Rightarrow x=\dfrac{2}{3}\)