(-4/3.7/8+5/8.4/3):(-3)
3..6+4.5-3.7*8.4=
A, 2/3+4/5+1/2 B, 7/8.4/9+7/8.5/9-(-1/8) C, 1/2+4/5-3/4
b) Ta có: \(B=\dfrac{7}{8}\cdot\dfrac{4}{9}+\dfrac{7}{8}\cdot\dfrac{5}{9}\)
\(=\dfrac{7}{8}\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\)
\(=\dfrac{7}{8}\cdot1=\dfrac{7}{8}\)
1,-8.4+19=
2,-11.3-28=
3,4.(-15)-18=
4,19-4.(-12)=
5,-25.(-3)-54=
6,-16-7.(-4)+24:(-8)=
7,15:(-3)+30-7.(-3)=
8,-48:(-4)+12.(-5)=
9,-29+65:(-5)+23=
10,15:(-5)-17-12.(-5)=
tính giá trị
a,\(\dfrac{\left(-3\right)^7.2^8}{6^7}\)
b,\(\dfrac{-3.7^4+7^3}{7^5.6-7^3.2}\)
c,\(\dfrac{5^3.3^5}{5^3.0.5+125.2.5}\)
a) \(\dfrac{\left(-3\right)^7\cdot2^8}{6^7}\)
\(=\dfrac{-1\cdot3^7\cdot2^8}{\left(2\cdot3\right)^7}=\dfrac{-1\cdot3^7\cdot2^7\cdot2}{2^7\cdot3^7}=-1\cdot2=-2\)
b) \(\dfrac{-3\cdot7^4+7^3}{7^5\cdot6-7^3\cdot2}\)
\(=\dfrac{-3\cdot7\cdot7^3+7^3}{7^3\cdot7^2\cdot6-7^3\cdot2}\)
\(=\dfrac{7^3\left(-3\cdot7+1\right)}{7^3\left(7^2\cdot6-2\right)}=\dfrac{-3\cdot7+1}{7^2\cdot6-2}\)
\(=\dfrac{-21+1}{294-2}=\dfrac{-20}{290}=\dfrac{-2}{29}\)
b) \(\dfrac{5^3\cdot3^5}{5^3\cdot0,5+125\cdot2\cdot5}\)
\(=\dfrac{5^3\cdot3^5}{5^3\cdot0,5+5^3\cdot2\cdot5}=\dfrac{5^3\cdot3^5}{5^3\left(0,5+2\cdot5\right)}\)
\(=\dfrac{3^5}{0,5+2\cdot5}=\dfrac{243}{10,5}=\dfrac{162}{7}\)
1, Tính :
a, A = 1.(-1)+3.(-1)^2+5.(-1)^3.7+(-1)^4+9.(-1)^5
b, 1-2-3+4+5-6-7+8+...+61-62-63-64
1, Tính :
a, A = 1.(-1)+3.(-1)^2+5.(-1)^3.7+(-1)^4+9.(-1)^5
b, 1-2-3+4+5-6-7+8+...+61-62-63-64
\(A=1.\left(-1\right)+3.\left(-1\right)^2+5.\left(-1\right)^3.7+\left(-1\right)^4+9.\left(-1\right)^5\)
\(A=1.\left(-1\right)+3.1+5.\left(-1\right).7+1+9.\left(-1\right)\)
\(A=\left(-1\right)+3+\left(-5\right).7+1+\left(-9\right)\)
\(A=-1+3-35+1-9\)
\(A=-41\)
thực hiện phép tính:\(\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6+8^4.3^5}-\frac{5^{10}.7^3-25^5.49^2}{125^3.7^3+5^9.14^3}\)
Bài 1:
a, x+1/2=3/8.4/5
b, 5/16:x-1/4=5/8
c,-1/4.x+3/7.x=2
d, 22/9-(x+1/2)^2=7/3
e, \(\frac{1}{4}-x+5\frac{1}{8}=6\frac{1}{8}\)
Giúp mik với, đang gấp lắm!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Tính tổng:a)3+3/5+3/25+3/125+3/625
b)M=4/3.7+4/7.11+4/11.15+...+8/95.99
c)N=1/2+1/6+1/12+1/20+...+1/90
Ta có : \(M=\frac{4}{3.7}+\frac{4}{7.11}+\frac{4}{11.15}+.....+\frac{4}{95.99}\)
\(=\frac{1}{3}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+......+\frac{1}{95}-\frac{1}{99}\)
\(=\frac{1}{3}-\frac{1}{99}\)
\(=\frac{32}{99}\)