Question

Câu 6 : Tìm x biết :

a) - 12 . ( x - 5 ) + 7 . ( 3 - x ) = 5

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Answer 1

-12.(x-5)+7.(3-x)=5

-12x+12.5+7.3-7x=5

-12x-7x=5-60-21

-19x=-76

x=-76:-19

x=4

Answer 2

\(-12\left(x-5\right)+7\left(3-x\right)=5\)

\(\Rightarrow-12x+60+21-7x=5\)

\(\Rightarrow-12x-7x=5-21-60\)

\(\Rightarrow-19x=-76\)

\(\Rightarrow x=4\)

Answer 3

-12.(x-5)+7.(3-x)=5

-12x+12.5+7.3-7x=5

-12x-7x=5-60-21

-19x=-76

x=-76:-19

x=4