Question

Tìm x biết:

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

mk cần gấp

Answer 1

Ta có : \(-12.\left(x-5\right)+7.\left(3-x\right)=5\)

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

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

\(\Rightarrow-19x+81=5\)

\(\Rightarrow-19x=5-81\)

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

\(\Rightarrow x=-76:\left(-19\right)\)

\(\Rightarrow x=4\)

Vậy x=4

Answer 2

x=4 đó

Answer 3

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

<=> -12x+60+21-7x=5

<=> -19x+81=5

<=> -19x=-76

<=>x= 4

Vậy x=4