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\(a.=\frac{3}{15}+\frac{-10}{15}\)
\(=-\frac{7}{15}\)
\(b.=\left(\frac{15}{12}-\frac{3}{12}\right)+\left(\frac{5}{13}-\frac{18}{13}\right)\)
\(=1+\left(-1\right)\)
\(=0\)
\(c.=\left(\frac{13}{25}-\frac{38}{25}\right)+\left(\frac{6}{41}+\frac{35}{41}\right)-\frac{1}{2}\)
\(=-1+1-\frac{1}{2}\)
\(=0-\frac{1}{2}\)
\(=-\frac{1}{2}\)
\(d.=\frac{5}{6}.\left(18\frac{2}{3}-6\frac{2}{3}\right)\)
\(=\frac{5}{6}.12\)
\(=10\)
a)(x-2)^4=4^4
=(x-2)=4 sr x=4+2
sr x=6
xin lỗi nha mình chỉ biết làm bài a thôi mong cậu thông cảm và kb với mình nhé
Mình biết bài nào làm bài đó thôi nhé
a) (x-2)4 = 256
=> x-2 = 4
x = 4+2
x = 6
b) \(\frac{x^4}{256}=81\)
\(\Rightarrow\frac{x^4}{4^4}=3^4\)
Từ đây có thể làm theo 2 cách khác nhau
C1 : \(\frac{x^4}{4^4}=81\)
\(\Rightarrow\left(\frac{x}{4}\right)^4=81\)
\(\Rightarrow\frac{x}{4}=3\)
x = 3.4
x = 12
C2 : \(\frac{x^4}{4^4}=3^4\)
=> x4 = 34.44
x4 = (3.4)4
x4 = 124
<=> x = 4
c) \(125.\left(x+\frac{4}{5}\right)^3=729\)
\(\left(x+\frac{4}{5}\right)^3=729:125\)
\(\left(x+\frac{4}{5}\right)^3=5,832\)
\(\Rightarrow x+\frac{4}{5}=1,8=\frac{9}{5}\)
\(x=\frac{9}{5}-\frac{4}{5}\)
\(x=\frac{5}{5}=1\)
\(a,=\left(\frac{15}{12}-\frac{3}{12}\right)+\left(\frac{5}{13}-\frac{18}{13}\right)\)
\(=1+-1\)
\(=0\)
( − 2 ) ⋅ − 38 21 ⋅ − 7 4 ⋅ − 3 8 = ( − 2 ) . ( − 38 ) . ( − 7 ) . ( − 3 ) 21.4.8 = 2.38.7.3 21.4.8 = 19 8 = 2 3 8
a) (x-2)\(^4\) = 256
(x-2)\(^4\) = \(4^4\)
x-2=4
x=4+2
x=6
b) \(\dfrac{x^4}{256}=81\)
\(\dfrac{x^4}{4^4}=81\)
\(\dfrac{x}{4}=81\)
x =81.4
x = 324
c) \(125\left(x+\dfrac{4}{5}\right)^3=729\)
\(\left(x+\dfrac{4}{5}\right)^3=729:125=\dfrac{729}{125}\)
\(\left(x+\dfrac{4}{5}\right)^3=\left(\dfrac{9}{5}\right)^3\)
\(x+\dfrac{4}{5}=\dfrac{9}{5}\)
x = \(\dfrac{9}{5}-\dfrac{4}{5}\)
x \(=1\)
a)
\(2^{n-1}:2=256\)
\(\Rightarrow2^{n-1}:2=2^8\)
\(\Rightarrow2^{n-1}=2^9\)
\(\Rightarrow n-1=9\)
\(\Rightarrow n=10\)
b)
\(5^n+5^{n-2}=650\)
\(\Rightarrow5^n+5^n:5^2=650\)
\(\Rightarrow5^n+5^n:25=650\)
\(\Rightarrow5^n+5^n.\dfrac{1}{25}=650\)
\(\Rightarrow5^n.\left(1+\dfrac{1}{25}\right)=650\)
\(\Rightarrow5^n.\dfrac{26}{25}=650\)
\(\Rightarrow5^n=625\)
\(\Rightarrow5^n=5^4\)
\(\Rightarrow n=4\)
c)
\(2^{n-3}+2^{n+1}=136\)
\(\Rightarrow2^n.\dfrac{1}{2^3}+2^n.2=136\)
\(\Rightarrow2^n.\left(\dfrac{1}{8}+2\right)=136\)
\(\Rightarrow2^n.\dfrac{17}{8}=136\)
\(\Rightarrow2^n=64\)
\(\Rightarrow2^n=2^6\)
\(\Rightarrow n=6\)