Câu1: 3² . 64 + 36 . 3²
Câu2: 5² . 69 + 31 . 5²
Câu3: 8² . 73 + 27 . 8²
Câu4: 9² . 125 - 25 . 9²
Câu1: 3² . 64 + 36 . 3²
Câu2: 5² . 69 + 31 . 5²
Câu3: 8² . 73 + 27 . 8²
Câu4: 9² . 125 - 25 . 9²
Câu1: 3² . 64 + 36 . 3²
=3² . (64 + 36 )
=9.100
=900
Câu2: 5² . 69 + 31 . 5²
= 5² .( 69 + 31)
=25.100
=2500
Câu3: 8² . 73 + 27 . 8²
8² .( 73 + 27)
=64.100
=6400
Câu4: 9² . 125 - 25 . 9²
=9² . (125 - 25 )
=81.150
=12150
Tính hợp lí (nếu có thể):
a) 2 . 31 . 12 + 4 . 6 . 42 + 8 . 27 . 3
b) (39 . 9 + 39 . 12) : 310
c) 36 . 28 + 36 . 82 + 64 . 69 + 64 . 41
d) [545 - (45 + 4 . 25)] : 50 - 2000 : 250 + 215 : 213
e) [504 - (25 . 8 + 70)] : 9 - 15 + 190
f) 5 . {26 - [3 . (5 + 2 . 5) + 15] : 15}
bài 2 viết mỗi tích, thương sau dưới dạng luỹ thừa
a) 4^10 x 2^30 b) 9^25 x 27^4 x 81^3 c) 25^50 x 125^5 d) 64^3 x 4^8 x 16^4
e)3^8:3^6 ; 2^10:8^3 ; 12^7 :6^7 ; 31^5 ; 81^3
f) 5^8 : 25^2 ; 4^9:64^2 ; 2^25 : 32^4 ; 125^3 : 25^4
a, 410. 230=220.230=250
b,925.274.813= 350.312.312=374
Tương tự các câu khác....
a, 410.230 = (22)10.230 = 220.230 = 250
b, 925.274.813 = (32)25.(33)4.(34)3 = 350.312.312 = 374
c, 2550.1255 = (52)50.(53)5 = 5100.515 = 5115
d, 643.48.164 = (26)3.(22)8.(24)4 = 218.216.216 = 250
e, 38 : 36 = 32
210 : 83 = 210 : (23)3 = 210 : 29 = 2
127 : 67 = (12 : 6)7 = 27
@Dương Tuyết Mai
Câu1: √(25x2 - 9) = 2 √(5x - 3)
Câu2: √(4x - 20) + √(x - 5) - 1/3 × √(9x - 45) = 4
Câu3: √(x - 8) + √(4x - 20) - 1/5 × √(9x - 45) = 3
Tính:
Câu1: 1+4+5+9+14+......+665 = ?
Câu2: 1+7+8+15+23+....419 = ?
Câu3: 1+7+9+15+23+....1775 = ?
cần cách giải nhanh
Câu1
(3-x):0,16 = -9:(x-3)
Câu2
x+1/2x+1=0,5x+2/x+3
Câu3
(x+y-1/2)^2+(x-y+1/6)^2=0
Câu4
x.(x-1/4)>0
Tính nhẩm: 1) 373737 . 73 - 37 . 737373 2)19 . 41414141 - 41 . 19191919 3)123456 . 456789456789 - 456789 . 123456123456 4)250 . 12 . 7 5)24 . 125 . 9 6)125 . 44 . 18 7)8 . 24 . 6 + 12 . 4 . 52 + 2 . 22 . 24 8)18. 58 . 2 - 9 . 27 . 4 + 12 . 69 . 3 9)30 . 85 . 3 + 18 . 72 . 5 - 45 . 37 . 2 - 9 . 20 . 10
1) \(373737.73-37.737373\)
\(=37.10101.73-37.73.10101\)
\(=0\)
2) \(19.41414141-41.19191919\)
\(=19.41.1010101-41.19.1010101\)
\(=0\)
3) \(123456.456789456789-456789.123456123456\)
\(=123456.456789.1000001-456789.123456.1000001\)
\(=0\)
4) \(250.12.7\)
\(=250.4.3.7\)
\(=\left(250.4\right).\left(3.7\right)\)
\(=1000.21\)
\(=21000\)
5) \(24.125.9\)
\(=3.8.125.9\)
\(=\left(3.9\right).\left(8.125\right)\)
\(=27.1000\)
\(=27000\)
6) \(125.44.18\)
\(=125.4.11.2.9\)
\(=\left(125.4.2\right).\left(11.9\right)\)
\(=1000.99\)
\(=99000\)
7) \(8.24.6+12.4.52+2.22.24\)
\(=48.24+48.52+48.22\)
\(=48\left(24+52+22\right)\)
\(=48.98\)
\(=48\left(100-2\right)\)
\(=48.100-48.2\)
\(=4800-96\)
\(=4704\)
8) \(18.58.2-9.27.4+12.69.3\)
\(=36.58-36.27+36.69\)
\(=36\left(58-27+69\right)\)
\(=36.100=3600\)
9) \(30.85.3+18.72.5-45.37.2-9.20.10\)
\(=90.85+90.72-90.37-90.20\)
\(=90\left(85+72-37-20\right)\)
\(=90.100=9000\)
\(\dfrac{45^{10}\cdot5^{20}}{75^{15}}\)
\(\dfrac{6^6+6^3+3^3+3^6}{-73}\)
\(\dfrac{27^7+3^{15}}{9^9-27}\)
\(\dfrac{8^{20}+4^{20}}{4^{25}+64^5}\)
\(\dfrac{45^{10}\cdot5^{20}}{75^{15}}=\dfrac{\left(3^2\cdot5\right)^{10}\cdot5^{20}}{\left(3\cdot5^2\right)^{15}}=\dfrac{3^{20}\cdot5^{10}\cdot5^{20}}{3^{15}\cdot5^{30}}=3^5=243\\ \dfrac{6^6+6^3+3^3+3^6}{-73}=\dfrac{46656+216+27+729}{-73}=-\dfrac{47628}{73}\\ \dfrac{27^7+3^{15}}{9^9-27}=\dfrac{\left(3^3\right)^7+3^{15}}{\left(3^2\right)^9-3^3}=\dfrac{3^{21}+3^{15}}{3^{18}-3^3}=\dfrac{3^{15}\left(3^6+1\right)}{3^3\left(3^{15}-1\right)}=\dfrac{3^5\cdot730}{3^{15}-1}\\ \dfrac{8^{20}+4^{20}}{4^{25}+64^5}=\dfrac{\left(2^3\right)^{20}+\left(2^2\right)^{20}}{\left(2^2\right)^{25}+\left(2^6\right)^5}=\dfrac{2^{60}+2^{40}}{2^{50}+2^{30}}=\dfrac{2^{40}\left(2^{20}+1\right)}{2^{30}\left(2^{20}+1\right)}=2^{10}=1024\)
a) 100 + 98 + 96 + ... + 2 - 97 - 95 - ... - 1
b) 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 - 11 - 12 + ... + 299 - 300 + 301 + 302
c) 2 . 31 . 12 + 4 .6 . 42 + 8 . 27 . 3
d) 36 . 28 + 36 . 82 + 64 . 69 + 64 . 41
e) 99 - 97 + 95 - 93 + 91 - 89 + ...+ 7 - 5 + 3 - 1
a, 100 + 98 + 96 + ... + 2 - 9 7 - 95 - .. -1
= 100 + (98 - 97) + (96-95) + ... + + ... + (2 - 1)
= 100 + 1 + 1 + 1 +.. +1
= 100 + 1 x49
= 100 + 49
= 149
b , 1 + 2 - 3 - 4 + 5 + 6 - .... -299 - 330 +301 + 302
=( 1 + 2 - 3) + ( -4 + 5 + 6 -7 ) +... +(298 - 299 -300 +301 ) + 302
= 0 + 0 + .. + 0 + 302
= 302
c) 2 . 31 . 12 + 4 . 6 . 42 + 8 . 27 . 3
=24.31+24.42+24.27
=24.(31+42+27)
=24.100
=2400
d)
=36x(28+82)+64x(69+41)
=36x110+64x110
=110x(26+64)
=110x100
=11000
d) dãy tính trên có số số tự nhiên là: (99-1):2+1=50(số)
99-97+95-93+91-89+...+7-5+3-1(50:2=25 cặp)
(99-97)+(95-93)+(91-89)+...+(7-5)+(3-1) (25 cặp)
2+2+2+2+2+...+2+2(25 số 2)
2x25=50