a) \(x:\dfrac{7}{11}-\dfrac{2}{3}=\dfrac{4}{5}\)

\(=>x:\dfrac{7}{11}=\dfrac{4}{5}+\dfrac{2}{3}=\dfrac{12}{15}+\dfrac{10}{15}\)

\(=>x:\dfrac{7}{11}=\dfrac{22}{15}\)

\(=>x=\dfrac{22}{15}.\dfrac{7}{11}\)

\(=>x=\dfrac{14}{15}\)

b) \(\dfrac{12}{11}:x+\dfrac{5}{6}=\dfrac{1}{2}\)

\(=>\dfrac{12}{11}:x=\dfrac{1}{2}-\dfrac{5}{6}=\dfrac{3}{6}-\dfrac{5}{6}\)

\(=>\dfrac{12}{11}:x=\dfrac{-2}{6}\)

\(=>x=\dfrac{12}{11}:\dfrac{-2}{6}=\dfrac{12}{11}.\dfrac{-6}{2}\)

\(=>x=\dfrac{-36}{11}\)

có

không

P={(a-3)-[a+3+a+2]}

P={a-3-2a-5}

P=-a-8

Q=[2a+3]-4

Q=2a-1

=>2a-1>-a-8

Hơi tắt nha bn

x=2 nha bn

a) \(2^3-5^3:5^2+12.2^2\)

\(=8-5+12.4\)

\(=8-5+48\)

\(=3+48\)

\(=51\)

b) \(5\left[\left(85-35:7\right):8+90\right]-50\)

\(=5\left[\left(85-5\right):8+90\right]-50\)

\(=5\left[80:8+90\right]-50\)

\(=5\left[10+90\right]-50\)

\(=5.100-50\)

\(=500-50\)

\(=450\)

c) \(2.\left[\left(7-3^3:3^2\right):2^2+99\right]-100\)

\(=2.\left[\left(7-3\right):4+99\right]-100\)

\(=2.\left[4:4+99\right]-100\)

\(=2.\left[1+99\right]-100\)

\(=2.100-100\)

\(=200-100\)

\(=100\)

d) \(2^7:2^2+5^4:5^3.2^4-3.2^5\)

\(=2^5+5.2^4-3.2^5\)

\(=32+5.16-3.32\)

\(=32+80-96\)

\(=112-96\)

\(=16\)

e) \(\left(3^5.3^7\right):3^{10}+5.2^4-7^3:7\)

\(=3^{12}:3^{10}+5.16-7^2\)

\(=3^2+80-49\)

\(=9+80-49\)

\(=89-49\)

\(=40\)

f) \(3^2.\left[\left(5^2-3\right):11\right]-2^4+2.10^3\)

\(=9.\left[\left(25-3\right):11\right]-16+2.1000\)

\(=9.\left[22:11\right]-16+2.1000\)

\(=9.2-16+2.1000\)

\(=18-16+2000\)

\(=2+2000\)

\(=2002\)

\(#WendyDang\)

Lời giải:
a.

\(A=\frac{-5}{2}-\frac{7}{3}-(-8)-9=\frac{-29}{6}+8-9=\frac{-29}{6}-1=-(\frac{29}{6}+1)=\frac{-35}{6}\)

b.

\(B=\frac{3^{11}(9+23)}{3^9.2^5}=\frac{3^{11}.32}{3^9.2^5}=\frac{3^{11}.2^5}{3^9.2^5}=3^2=9\)

Để \(\dfrac{n+4}{n+1}\)nhận giá trị nguyên thì \(n+4⋮n+1\)

\(n+4⋮n+1\\ =>n+1+3⋮n+1\\ =>3⋮n+1\\ n+1\inƯ\left(3\right)=\left\{-3;-1;1;3\right\}\\ =>n\in\left\{-4;-2;0;2\right\}\)

Vậy \(n\in\left\{-4;-2;0;2\right\}\) nên \(n+4⋮n+1\)hay  \(\dfrac{n+4}{n+1}\)nhận giá trị nguyên

xin lỗi mình viết nhầm

từ nên thay bằng từ thì nhé

a) −54 − (36 − 45) = −54 − (−9) = −54 + 9 = −45
b) 26 − (−43 − 33) = 26 − (−76) = 26 + 76 = 102
c) 52 − [31 + (3^0  − 2)] = 52 − [31 + (1 − 2)] = 52 − [31 − 1] = 52 − 30 = 22
d) 1/5 + 1/6 = 6/30 + 5/30 = 11/30
e) 5/7 + 8/14 = 10/14 + 8/14 = 18/14 = 9/7
b) 9/10 + 12/6 = 9/10 + 20/10 = 29/10
k) 5/4 - 7/8 + 6/5 = 50/40 - 35/40 + 48/40 = 63/40