Question

[phamhoangthienanh]

Giúp mk vs 

Tìm x 

a, ( x - 5 ) ^4 = ( x - 5 ) ^ 6 

b , ( 2x - 15 ) ^ 5 = ( 2x -15 ) ^ 3 

Answer 1

[Mikasa Ackerman]

a/(x-5)^4=9x-5)^6\(\Rightarrow\) TH1:x-5=1\(\rightarrow\) x=6

                        \(\Rightarrow\) TH2:x-5=-1\(\rightarrow\) x=4

                       \(\Rightarrow\) TH3:x-5=0\(\rightarrow\) x=5

vậy....................

b/(2x-15)^5=(2x-15)^6\(\Rightarrow\) 2x-15=1\(\rightarrow\) 2x=16\(\rightarrow\)x=8

                              \(\Rightarrow\) 2x-15=0\(\rightarrow\)2x=15\(\rightarrow\)x=7.5

vậy................

Answer 2

[Thúy Ngân]

a) Có : ( x-5 ) \(^4\) = ( x - 5 ) \(^6\)

\(\Rightarrow\left(x-5\right)^6:\left(x-5\right)^4=1\Rightarrow\left(x-5\right)^2=1\)

\(\Rightarrow x-5=1\) hoặc \(x-5=-1\)

\(\Rightarrow x=1+5\) hoặc \(x=-1+5\)

\(\Rightarrow x=6\) hoặc \(x=4\)

b) \(\left(2x-15\right)^5=\left(2x-15\right)^3\)

\(\Rightarrow\left(2x-15\right)^5:\left(2x-15\right)^3=1\Rightarrow\left(2x-15\right)^2=1\)

\(\Rightarrow2x-15=1\) hoặc \(2x-15=-1\)

\(\Rightarrow2x=16\) hoặc \(2x=14\)

\(\Rightarrow x=8\) hoặc \(x=7\)