Toán Lớp 7: Tìm x trong đẳng thức: d) $(2x+1)^{4}$ = $(2x+1)^{6}$
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Toán Lớp 7: Tìm x trong đẳng thức: d) $(2x+1)^{4}$ = $(2x+1)^{6}$
Comments ( 2 )
(2x+1)^4=(2x+1)^6
=>(2x+1)^4-(2x+1)^6=0
=>(2x+1)^4 . 1-(2x+1)^4 . (2x+1)^2=0
=>(2x+1)^4 . [1-(2x+1)^2]=0
=>[((2x+1)^4=0),(1-(2x+1)^2=0):}
=>[(2x+1=0),((2x+1)^2=1):}
=>[(2x=-1),([(2x+1=1),(2x+1=-1):}):}
=>[(x=-1/2),([(2x=0),(2x=-2):}):}
=>[(x=-1/2),([(x=0),(x=-1):}):}
Vậy x\in{-1/2;0;-1}