Question

tìm x

a) 3x + 12 = 2x - 4

b) 14 - 3x = -x + 4

c) ( 2x - 8 ) ( x + 6 ) = 0

Answer 1

a) 3x + 12 = 2x - 4

=> 3x - 2x = -4 - 12

=> 1x = -16

=> x = -16

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b) 14 - 3x = -x + 4

=> 14-4 = -x+3x

=> 10 = 2x

=> x = 10 : 2

=> x = 5

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\(c) ( 2x - 8 ) ( x + 6 ) = 0\)

\(\Rightarrow\orbr{\begin{cases}2x-8=0\\x+6=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=4\\x=-6\end{cases}}\)

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