1, tính nhanh
a, 36.28+36.82+64.69+64.41
B, 13,5.5,8-8,3.4,2-5,8.8,3+4,2.14,5
C, 4,8.13,3+4,8.6,7+5,2.13,3+5,2.6,7
D, 7,8.55,1+92,2.55,1-7,8.5,1-99,2.5,1
E, 85.12,7+5.3.12,7
F, 52.143-52.39-8.26
G, 13.49+18.49-25.49+49.7
2, tìm x
(6x+11)(5y-12)-42x+66=0
Hơi mờ
Câu 2 không biết làm
tính nhanh
a/13,5.5,8-8,3.4,2-5,8.8,3+4,2.13,5
b/7,8.55,1+92,2.55,1-7,8.5,1-92,2.5,1
c/N=a^3-a^2b-ab^2+b^3 khi a=5,75 ;b=4,25
a) \(13,5\times5,8-8,3\times4,2-5,8\times8,3+4,2\times13,5\)
\(=13,5\times\left(5,8+4,2\right)-8,3\times\left(4,2+5,8\right)\)
\(=10\times\left(13,5-8,3\right)=10\times5,2=52\)
b) \(7,8\times55,1+92,2\times55,1-7,8\times5,1-92,2\times5,1\)
\(=55,1\times\left(7,8+99,2\right)-5,1\times\left(7,8+99,2\right)\)
\(=100\times\left(55,1-5,1\right)=100\times50=5000\)
c) \(N=a^3-a^2b-ab^2+b^3=\left(a-b\right)^2\left(a+b\right)\)
\(=\left(5,75-4,25\right)^2.\left(5,75+4,25\right)=1,5^2\times10=22,5\)
Phân tích đa thức thành nhân tử
13,5.5,8-8,3.4,2-5,8.8,3+4,2.13,5
13.5 x 5.8 - 8.3 x 4.2 - 5.8 x 8.3 + 4.2 x 13.5
= ( 13.5 x 5.8 + 4.2 x 13.5 ) - ( 8.3 x 4.2 + 5.8 x 8.3 )
= 13.5 x ( 5.8 + 4.2 ) - 8.3 x ( 4.2 + 5.8 )
= 13.5 x 10 - 8.3 x 10
= ( 13.5 - 8.3 ) x 10
= 5.2 x 10
= 52
Bài 7: Tính nhanh
a) 37. 38 + 62. 37 b) 28. 64 + 28. 36
c) 3. 25. 8 + 4. 37. 6 + 2. 38. 12 d) (1200 + 60) : 12
e) 12.53 + 53. 172 – 53. 84 g) (2100 – 42) : 21
h) 39.8 + 60.2 + 21.8 i) 36.28 + 36.82 + 64.69 + 64.41
k) 32. 47 + 32. 53 l) 37.7 + 80.3 +43.7
m) 113.38 + 113.62 + 87.62 + 87.38 n) 123.456 + 456.321 –256
a. 37. 38 + 62. 37
= 37 . (38 + 62)
= 37 . 100
= 3700
b. 28. 64 + 28. 36
= 28 . (64 + 36)
= 28 . 100
= 2800
c. 3. 25. 8 + 4. 37. 6 + 2. 38. 12
= 3 . 8 . 25 + 4 . 6 . 37 + 12 . 2 . 38
= 24 . 25 + 24 . 37 + 24 . 38
= 24 . (25 + 37 + 38)
= 24 . 100
= 2400
Tính nhanh: 36.28 + 36.82 + 64.69 + 64.41
36.28 + 36.82 + 64.69 + 64.41
= (36.28 + 36. 82) + ( 64.69 + 64.41)
= 36.(28 + 82) + 64.(69 + 41)
= 36.110 + 64.110 = 110.( 36 + 64 ) = 110.100 = 11000
1. TÍNH NHANH:
36.28+36.82+64.69+64.41
36.28 + 36.82 + 64.69 + 64.41 = 36.(28 + 82) + 64.(69 + 41) = 36.110 + 64.110 = (36 + 64).110 = 100.110 = 11000
\(36x28+36x82+64x69+64x41\)
\(=36x\left(28+82\right)+64x\left(69+41\right)\)
\(=36x110+64x110\)
\(=\left(36+64\right)x110\)
\(=100x110\)
\(=11000\)
=36.(28+82)+64.(69+41)
=36.110+64.110
=(36+64).110
=100.110
=11000
k minh nha
Tính nhanh :
a) \(85.12,7+5.3.12,7\)
b) \(52.143-52.39-8.26\)
a) 85.12,7+5,3.12,7
=12,7(85+5,3)=1146,81
b) 52.143-52.39-8.26
=52.(143-39)-208
= 5200
=
36.28+36.82+64.69.+64.41
36.28+36.82+64.69+64.41
=36.(28+82)+64.(69+41)
=36.110+64.110
=(36+64).110
=100.110
=11000
36 . 28 + 36 . 82 + 64 . 69 + 64 . 41
= 36( 28 + 82 ) + 64( 69 + 41 )
= 36 . 110 + 64 . 110
= 110 ( 36 + 64 )
= 110 . 100
= 11000
36.28+36.82+64.69+64.41
Ta có:36.28+36.82+64.69+64.41
=36.(28+82)+64.(69+41)
=36.110+64.110
=110.(36+64)
=110.100
=11000
Nhớ bấm đúng cho mình nếu thấy đúng nha!
