Question

a)|x-5|=|-7|

b) |x-3|=7-(-2)

c) (7-x)-(25+7)=-25

Answer 1

b) |x-3|=7 - (-2)

|x-3| = 9

TH 1 : TH 2 :

x - 3 = 9 x - 3 = -9

x = 9 + 3 x = -9 + 3

x = 12 x = 6

Answer 2

c) (7-x)-(25+7)=-25

(7-x) = -25 + 25 - 7

(7-x) = - 7

x = -7 + 7

x = 0

Answer 3

a) |x-5| = |-7|

|x-5| = 7

\(\Rightarrow\left[{}\begin{matrix}x-5=7\\x-5=-7\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=7+5\\x=\left(-7\right)+5\end{matrix}\right.\Rightarrow}\left[{}\begin{matrix}x=12\\x=2\end{matrix}\right.\)

Vậy x \(\in\) { 12;-2}

b) |x-3| = 7 - ( - 2 )

|x-3| = 7 + 2

|x-3| = 9\(\Rightarrow\left[{}\begin{matrix}x-3=9\\x-3=-9\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=9+3\\x=\left(-9\right)+3\end{matrix}\right.\Rightarrow}\left[{}\begin{matrix}x=12\\x=-6\end{matrix}\right.\)

Vậy x \(\in\) { 12 ; -6 }

c) ( 7 - x ) - ( 25 + 7 ) = - 25

( 7 - x ) - 32 = - 25

7 - x = ( - 25 ) + 32

7 - x = 7

x = 7 - 7

x = 0

Answer 4

a)|x-5|=|-7|

|x-5| = 7

TH 1 : TH 2 :

x - 5 = 7 x - 5 = - 7

x = 7 + 5 x = - 7 + 5

x = 12 x = -2