Tinh nhanh :
2 x 18 x 14 + 3 x 17 x 12 + 4 x 69 x 6
tính nhanh: 2 x 18 x 14 + 3 x 17 x 12 + 4 x 69 x 9
2 x 18 x 14 + 3 x 17 x 12 + 4 x 69 x 9
=(2 x 18) x 14 + (3 x 12) x 17 + (4 x 9) x 69
=36 x 4 + 36 x 17 + 36 x 69
= 36x( 4+17+69)
=36x100
=3600
Chúc bạn học tốt ^_^
2 x 18 x 14 + 3 x 17 x 12 + 4 x 69 x 9
=(2 x 18) x 14 + (3 x 12) x 17 + (4 x 9) x 69
=36 x 4 + 36 x 17 + 36 x 69
= 36x( 4+17+69)
=36x100+
=3600
\(2.18.14+3.17.12+4.69.9\)
\(=\left(2.18\right).14+\left(3.12\right).17+\left(4.9\right).69\)
\(=36.4+36.17+36.69\)
\(=36.\left(4+17+69\right)\)
\(=36.100\)
\(=3600\)
~ Rất vui vì giúp đc bn ~
1. 27 x 75 + 25 x 75 - 150
2. 15 x 23 + 15 x 37 + 40 + 15
3. 4 x 9 x 14 + 3 x 17 x 12 + 2 x 69 x 18
4. 32 x ( 157 + 43) + 68 x ( 157 + 43)
1: \(=75\left(27+25-2\right)=75\cdot50=3750\)
2: \(=15\left(23+37\right)+55=15\cdot60+55=955\)
3: \(=36\cdot14+36\cdot17+36\cdot69\)
\(=36\cdot100=3600\)
4: \(=200\cdot\left(32+68\right)=200\cdot100=20000\)
. Tính bằng cách hợp lí :
2 x 18 x 14 + 3 x 17 x12 + 4 x 69 x 9
2 x 18 x 14 + 3 x 17 x 12 + 4 x 69 x 9
= { 2 x 18 } x 14 + { 12 x 3 } x 17 + { 4 x 9 } x 69
= 36 x 14 + 36 x 17 + 36 x 69
= 36 x { 14 + 17 + 69 }
= 36 x 100
= 3600
2 × 18 × 14 + 3 × 17 × 12 + 4 × 69 × 9
= 2 × 18 × 14 + 3 × 12 × 17 + 4 × 9 × 69
= 36 × 14 + 36 × 17 + 36 × 69
= 36 × (14 + 17 + 69)
= 36 × 100
= 3600
2 x 18 x 14 + 3 x 17 x 12 + 4 x 69 x 9
= { 2 x 18 } x 14 + { 12 x 3 } x 17 + { 9 x 4 } x 69
= 36 x 14 + 36 x 17 + 36 x 69
= 36 x { 14 + 17 + 69 }
= 36 x 100
= 3 600
2023 x 14 + 2023 x 83 +97
78 x 31 + 78 x 24 + 78 x 17 + 78 x 22 x 72
371 x 69 + 371 x 14 + 629 x 83
91 x 51 + 49 x 163 - 49 x 72
3 x 12 x 17 + 4 x 9 x 81 + 2 x 6 x 6
42 x 17 + 58 x 83 x 42 x 83 + 42 x 83 + 58 x 17
tính bằng cách hợp lý nhất
`@` `\text {Ans}`
`\downarrow`
`2023 \times 14 + 2023 \times 83+97`
`= 2023 \times (14+83) + 97`
`= 2023 \times 97 + 97`
`= 196231 +97`
`= 196328`
`78 \times 31+78 \times 24+78 \times 17+78 \times 22 \times 72`
`= 78 \times (31+24+17+22 \times 72)`
`= 78 \times (31+24+17+1584)`
`= 78 \times 1656`
`= 129168`
`371 \times 69+371 \times 14+629 \times 83`
`= 371 \times (69+14) + 629 \times 83`
`= 371 \times 83 + 629 \times 83`
`= 83 \times (371+629)`
`= 83 \times 1000`
`= 83000`
`91 \times 51+49 \times 163-49 \times 72`
`= 91 \times 51 + 49 \times (163-72)`
`= 91 \times 51+49 \times 91`
`= 91 \times (51+49)`
`= 91 \times 100`
`= 9100`
`3 \times 12 \times 17 + 4 \times 9 \times 81 + 2 \times 6 \times 6`
`= 9 \times 4 \times 17 + 4 \times 9 \times 81 + 4 \times 9 \times 2`
`= 9 \times 4 \times (17+81+2)`
`= 36 \times 100`
`= 3600`
`42 \times 17 + 58 \times 83 \times 42 \times 83 + 42 \times 83 + 17`
`= 17 \times (42+58) + 42 \times 83 \times (58 \times 83 +1)`
`= 17 \times 100 + 3486 \times 4815`
`= 1700 + 16785090`
`= 16786790`
a,-8/3+7/5+-71/15<x<-13/7+19/14+-7/2
b,-19/6+-15/2+11/3<x<-5/4+19/12+-10/3
c,-6/7+3/35<x<-2/5+3/7
d,x=3/4+1/-12
e,x/14=1/7+-3/14
f,11/18+13/6=85/x
g,8/17+5/17<x/17<6/17+9/17
a,-8/3+7/5+-71/15<x<-13/7+19/14+-7/2
b,-19/6+-15/2+11/3<x<-5/4+19/12+-10/3
c,-6/7+3/35<x<-2/5+3/7
d,x=3/4+1/-12
e,x/14=1/7+-3/14
f,11/18+13/6=85/x
g,8/17+5/17<x/17<6/17+9/17
mong các bn giúp đỡ mk vs mk cần rát gấp
ai nhanh giúp mk thì mk tick cho 3 tick mk thề có lòng tự trọng
ai lm nhanh mk cho 10 tick lun nhanh nha đang cần gấp
các bn lm đến đâu cx dc miễn là lm hộ mk cái ạ, ai đang lm vào nhắn tin vs mk để mk bít nha
a; \(-\dfrac{8}{3}+\dfrac{7}{5}-\dfrac{71}{15}< x< -\dfrac{13}{7}+\dfrac{19}{14}-\dfrac{7}{2}\)
-\(\dfrac{19}{15}\) - \(\dfrac{71}{15}\) < \(x\) < -\(\dfrac{1}{2}\) - \(\dfrac{7}{2}\)
-6 < \(x\) < -4
vì \(x\) \(\in\) Z nên \(x\) = -5
- \(\dfrac{19}{6}+\dfrac{-15}{2}+\dfrac{11}{3}\) < \(x\) < - \(\dfrac{5}{4}\) + \(\dfrac{19}{12}\) - \(\dfrac{10}{3}\)
- \(\dfrac{32}{3}+\dfrac{11}{3}< x< \) \(\dfrac{1}{3}\) - \(\dfrac{10}{3}\)
-7 < \(x\) < - 3
Vì \(x\in\) Z nên \(x\in\) {-6;-5;-4}
1) (-49) - x - 13= (-6)
2) 74+ x - (-12)= 5
3) 21-( 29 + x ) = (-12)
4) 14-(x-17)=(-31)
5) (-5) (3-x)= (-15)+30
6) (-2)5 - (-x)= (-19)
7) (-18)-(x-17)=12
8) (-15) - ( x - 7 ) = 23
9) x là bội của 6 và (-8)<x<13
Ai giải nhanh, hết luôn mình tick nha nhớ ghi cách giải
1)x=-30
2)x=-81
3)x=4
4)x=62
5)x=6
6)-13
7)-13
8)-31
9)x=-6;0;6;12
tk minh nha
Bài 6: Thực hiện phép tính
a)(-18)-(-3)-12
b)85.(35-27)-35.(85-27)
c)(-45).69+31.(-45)
Bài 7:Tìm x thuộc Z, biết:
a)(2-x)+10=-14
b)14.|x|=28
c)31-(17+x)=55
Bài 6:
a)\(\left(-18\right)-\left(-3\right)-12\)
\(=\left(-18\right)+3-12\)
\(=-15-12\)
\(=-27\)
b)\(85.\left(35-27\right)-35.\left(85-27\right)\)
\(=85.35-85.27-35.85+35.27\)
\(=85.\left(35-27-35\right)+35.27\)
\(=85.\left(-27\right)+35.27\)
\(=27.\left(-85+35\right)\)
\(=27.\left(-50\right)\)
\(=-1350\)
c)\(\left(-45\right).69+31.\left(-45\right)\)
\(=\left(-45\right).\left(69+31\right)\)
\(=\left(-45\right).100\)
\(=-4500\)
Bài 7:
a)\(\left(2-x\right)+10=-14\)
\(\Rightarrow2-x=-24\)
\(\Rightarrow x=26\)
b)\(14.\left|x\right|=28\)
\(\Rightarrow\left|x\right|=2\)
\(\Rightarrow\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)
c)\(31-\left(17+x\right)=55\)
\(\Rightarrow17+x=-24\)
\(\Rightarrow x=-41\)
(-18)-(-3)-12=-27
85.(35-27)-35.(85-27)=-1350
(-45).69+31.(-45)=-4500
(2-x)+10=-14
\(\Leftrightarrow\)(2-x)=-14-10
\(\Leftrightarrow\)2-x=-24
\(\Rightarrow\)x=2-(-24)
\(\Rightarrow\)x=26
14.lxl=28
\(\Leftrightarrow\)lxl=28:14
\(\Leftrightarrow\)lxl=2
\(\Rightarrow\)x=-2
Tính nhanh:
11 x 12 + 12 x 13 + 13 x 14 + 14 x 15 + 15 x 16 + 16 x 17 + 17 x 18 + 18 x 19 + 19 x 20 + 20 x 21
11 x 12 + 12 x 13 + 13 x 14 + 14 x 15 + 15 x 16 + 16 x 17 + 17 x 18 + 18 x 19 + 19 x 20 + 20 x 21
= 12 x ( 11 + 13 ) + 14 x ( 13 + 15 ) + 16 x ( 15 + 17 ) + 18 x ( 17 + 19 ) + 20 x 21
= 12 x 24 + 14 x 28 + 16 x 32 + 18 x 36 + 420
= 288 + 392 + 512 + 648 + 420
= ( 288 + 392 ) + ( 512 + 648 ) + 420
= 680 + 1160 + 420
= 1840 + 420
= 2260
tk nha
=
Ta có:
11 x 12 + 12 x 13 + 13 x 14 + 14 x 15 + 15 x 16 + 16 x 17 + 17 x 18 + 18 x 19 + 19 x 20 + 20 x 21
= 12 x ( 11 + 13 ) + 14 x ( 13 + 15 ) + 16 x ( 15 + 17 ) + 18 x ( 17 + 19 ) + 20 x 21
= 12 x 24 + 14 x 28 + 16 x 32 + 18 x 36 + 420
= 288 + 392 + 512 + 648 + 420
= ( 288 + 392 ) + ( 512 + 648 ) + 420
= 680 + 1160 + 420
= 1840 + 420
= 2260
#Mạt Mạt#
11 x 12 + 12 x 13 + 13 x 14 + 14 x 15 + 15 x 16 + 16 x 17 + 17 x 18 + 18 x 19 + 19 x 20 + 20 x 21
= 12 x ( 11 + 13 ) + 14 x ( 13 + 15 ) + 16 x ( 15 + 17 ) + 18 x ( 17 + 19 ) + 20 x ( 19 + 21 )
= 12 x 24 + 14 x 28 + 16 x 32 + 18 x 36 + 20 x 40
= 288 + 392 + 512 + 648 + 800
= ( 288 + 392 ) + ( 512 + 648 ) + 800
= 680 + 1160 + 800
= 2640