25+(-8)+(-25)+(-2)-(-2)
Cho phép tính sau: (25+7) : (56−25)× ( 8 : 3) :2+64 ×3%
Phép tính nào thực hiện được trong chương trình bảng tính?
A.
=(25+7)/(56-25)x(8/3)/2+6^4x3%
B.
=(25+7)/(56-2^5)x(8/3):2+6^4x3%
C.
=(25+7)/(56-25)*(8/3)/2+64* 3%
D.
=(25+7)/(56-2/5)x(8/3)/2+6^4x3%
25+25+25+25+2+24+232+2+7+7+7+8+5+8+5+8+5+8+5+8+5+888888888888888+88888888888888888888888888888888888888888888+8+8+8+8+8+9+9+9+9+
bổ ai mà giải được
]`+'[
lấy máy tính mà tính
Tính nhanh nếu có thể: (25-11^2) . ( 25-10^2) . (25 - 9^2) . (25 - 8^2) ... (25 - 2^2) . (25 -1^2)
\(\left(25-11^2\right)\left(25-10^2\right)\left(25-9^2\right)...\left(25-5^2\right)\left(25-4^2\right)\left(25-3^2\right)\left(25-2^2\right)\left(25-1^2\right)\)
\(=\left(25-11^2\right)\left(25-10^2\right)\left(25-9^2\right)...\left(25-25\right)\left(25-4^2\right)\left(25-3^2\right)\left(25-2^2\right)\left(25-1^2\right)\)
\(=\left(25-11^2\right)\left(25-10^2\right)\left(25-9^2\right)...0.\left(25-4^2\right)\left(25-3^2\right)\left(25-2^2\right)\left(25-1^2\right)\)
\(=0\)
Tính nhanh nếu có thể: (25-11^2) . ( 25-10^2) . (25 - 9^2) . (25 - 8^2) ... (25 - 2^2) . (25 -1^2)
\(\left(25-11^2\right)\left(25-10^2\right)\left(25-9^2\right)...\left(25-5^2\right)\left(25-4^2\right)\left(25-3^2\right)\left(25-2^2\right)\left(25-1^2\right)\)
\(=\left(25-11^2\right)\left(25-10^2\right)\left(25-9^2\right)...\left(25-25\right)\left(25-4^2\right)\left(25-3^2\right)\left(25-2^2\right)\left(25-1^2\right)\)
\(=\left(25-11^2\right)\left(25-10^2\right)\left(25-9^2\right)....0.\left(25-4^2\right)\left(25-3^2\right)\left(25-2^2\right)\left(25-1^2\right)\)
\(=0\)
a) 25 - y^2 = 8(x+2009)^2 \Leftrightarrow 8(x+2009)^2 + y^2 = 25
Do y^2 \geq 0 \Rightarrow (x+2009)^2 \leq 25/8
\Rightarrow x+2009 =0 hoặc 1
Nếu x+2009 = 1 \Rightarrow 25 - y^2 = 1\Rightarrow y^2 = 26 (không tìm được y)
Nếu x+2009 = \Rightarrow 25 - y^2 = 0\Rightarrow y^2 = 25, y=5
Vậy (x=0;y=5)
\(\dfrac{1}{25}+\dfrac{2}{25}+\dfrac{3}{25}+\dfrac{4}{25}+\dfrac{6}{25}+\dfrac{7}{25}+\dfrac{8}{25}+\dfrac{9}{25}+\dfrac{10}{25}\)
A = 9/8 - 8/9 + 3/25 + 1/4 - 5/16 + 19/25 - 1/9 + 2/25 - 1/81
B = -1/3- 8/35 - 2/9 - 1/35 + 4//5 + -4/9 + 3/7
\(A=\dfrac{9}{8}-\dfrac{8}{9}+\dfrac{3}{24}+\dfrac{1}{4}-\dfrac{5}{16}+\dfrac{19}{25}-\dfrac{1}{9}+\dfrac{2}{25}-\dfrac{1}{81}\)
\(=\dfrac{9}{8}+\dfrac{1}{4}-\dfrac{5}{16}+\dfrac{1}{8}-\dfrac{8}{9}-\dfrac{1}{9}-\dfrac{1}{81}+\dfrac{19}{25}+\dfrac{2}{25}\)
\(=\dfrac{10}{8}+\dfrac{1}{4}-\dfrac{5}{16}-1-\dfrac{1}{81}+\dfrac{21}{25}\)
\(=\dfrac{20+4-5}{16}-\dfrac{82}{81}+\dfrac{21}{25}\)
\(=\dfrac{19}{16}-\dfrac{82}{81}+\dfrac{21}{25}\)
\(=\dfrac{32891}{16\cdot81\cdot25}\)
b: \(B=-\dfrac{1}{3}-\dfrac{8}{35}-\dfrac{2}{9}-\dfrac{1}{35}+\dfrac{4}{5}-\dfrac{4}{9}+\dfrac{3}{7}\)
\(=\dfrac{-1}{3}-\dfrac{2}{9}-\dfrac{4}{9}-\dfrac{8}{35}-\dfrac{1}{35}+\dfrac{4}{5}+\dfrac{3}{7}\)
\(=\dfrac{-3-2-4}{9}+\dfrac{-9}{35}+\dfrac{28+15}{35}\)
\(=-1+\dfrac{-9+43}{35}=-1+\dfrac{34}{35}=-\dfrac{1}{35}\)
4 x 125 x 25 x 8
2 x 8 x 50 x 25 x 125
2 x 3 x 4 x 5 x 50 x 25
25 x 20 x 125 x 8 - 8 x 20 x 5 x 125
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