Question

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Answer 1

b) \(\left(x-3\right)^2=16\)

\(x-3=4\) hoặc \(x-3=-4\)

*) \(x-3=4\)

\(x=4+3\)

\(x=7\)

*) \(x-3=-4\)

\(x=-4+3\)

\(x=-1\)

Vậy \(x=-1\); \(x=7\)

c) \(23+5x-2x=5^6:5^3\)

\(3x=5^3-23\)

\(3x=125-23\)

\(3x=102\)

\(x=\dfrac{102}{3}\)

\(x=34\)

Vậy \(x=34\)

d) \(3^{2\left(x-1\right)}=9\)

\(3^{2\left(x-1\right)}=3^2\)

\(2\left(x-1\right)=2\)

\(x-1=\dfrac{2}{2}\)

\(x-1=1\)

\(x=1+1\)

\(x=2\)

Vậy \(x=2\)

e) \(720:\left[41-\left(2x-5\right)\right]=2^3.5^1\)

\(720:\left[41-\left(2x-5\right)\right]=8.5\)

\(720:\left[41-\left(2x-5\right)\right]=40\)

\(41-\left(2x-5\right)=720:40\)

\(41-\left(2x-5\right)=18\)

\(2x-5=41-18\)

\(2x-5=23\)

\(2x=23+5\)

\(2x=28\)

\(x=\dfrac{28}{2}\)

\(x=14\)

Vậy \(x=14\)