10.2y-1+4-2y = 9.25
Tìm số nguyên n, biết
1 ) 2 − 1 .2 n + 4.2 n = 9.2 5
2 ) 1 2 .2 n + 4.2 n = 9.2 5
3 ) 32 − n .16 n = 2048
4 ) 5 2 n + 1 = 125 n + 25
tính bằng cách thuận tiện nhất:
a)9.25+9 5x8+9.25
b)14/15 + 3/11 + 1/15 + 3/11 + 10/22
Tính:
-5/9.13 -7/9.25 - 13 / 9.25 - 31 / 19. 69
9.25^9+25^9.(-1)+25^0+25^9
9.83 + (-2.33) - (-3.75) + 9.25 - 12.5
9.83 + (-2.33) - (-3.75) + 9.25 - 12.5
= 7,5 - (-3.75) + 9.25 - 12.5
= 11,25 + 9,25 - 12,5
= 20,5 - 12,5
= 8
=7,5+3,75+9,25-12,5
=20,5-12,5
=8
9.83 + (-2.33) - (-3.75) + 9.25 - 12.5
= 7,5 - (-3.75) + 9.25 - 12.5
= 11,25 + 9,25 - 12,5
= 20,5 - 12,5
= 8
3^x*5^x=9.25
\(3^x.5^x=9.25\)
\(\Rightarrow3^x.5^x=3^2.5^2\)
\(\Rightarrow\left(3.5\right)^x=\left(3.5\right)^2\)
\(\Rightarrow x=2\)
Vậy \(x=2\)
Hãy rút gọn 5.(-6) phần 9.25
\(\frac{5.\left(-6\right)}{9.25}\)\(=\frac{5.3.\left(-2\right)}{3.3.5.5}=\frac{-2}{3.5}=-\frac{2}{15}\)
\(\frac{5\times-6}{9\times25}\)= \(\frac{-30}{225}\)=\(\frac{-2}{15}\)
\(\frac{5.\left(-6\right)}{9.25}=\frac{5.3.\left(-2\right)}{3.3.5.5}=\frac{-2}{3.5}=\frac{-2}{15}\)
E=5/9.13+7/9.25+13/19.25+31/19.69
Bài 1:Thực hiện phép tính (hợp lí nếu có)
a,2.8^4.27^2+.6^9/2^7.6^7+27.40.9^4
b,(112/13.20+112/20.27+112/27.34+...+112/62.69):(5/9.13-7/9.25-13/19.25-31/19.69)
c,So sánh : A=1/2^1+1/2^2+...+1/2^49+1/2^50 với 1
c) Ta co : A=1/2^1+1/2^2+...+1/2^49+1/2^50
2A=1+1/2+1/2^2+........+1/2^48+1/2^49
A=1-1/2^50<1
Vậy A=1/2^1+1/2^2+...+1/2^49+1/2^50 <1