Mọi người giúp em giúp em với ạ! Em c.ơn^^

$@_Nmai_$

Đáp án + giải thích bước giải :

Bài ` 4 ` :

` a) ` $\text{987 - ( x + 14 ) = 678}$

$\text{x + 14 = 987 - 678}$

$\text{x + 14 = 309}$

$\text{x = 309 - 14}$

$\text{x = 295}$

` b) ` $\text{345 -( x - 65 ) = 324}$

$\text{x - 65 = 345 - 324}$

$\text{x - 65 = 21}$

$\text{x = 21 + 65}$

$\text{x = 86}$

` c) ` $\text{675 - ( 450 - x ) = 475}$

$\text{450 - x = 675 - 475}$

$\text{450 - x = 200}$

$\text{x = 450 - 200}$

$\text{x = 250}$

` d) ` $\text{( 255 - x ) - 67 = 189 - 67}$

$\text{( 255 - x ) - 67 = 122}$

$\text{255 - x = 122 + 67}$

$\text{255 - x = 189 }$

$\text{x = 255 - 189}$

$\text{x = 36}$

Bài ` 5 ` :

$\text{a ) 245 + ( 25 + x ) = 350}$

$\text{25 + x = 350 - 245}$

$\text{25 + x = 105}$

$\text{x = 105 - 25}$

$\text{x = 80}$

$\text{b) 250 + ( 120 - x ) = 365}$

$\text{120 - x = 365 - 250}$

$\text{120 - x = 115}$

$\text{x = 120 - 115}$

$\text{x = 5}$

$\text{c ) ( x - 103 ) + 47 = 167 - 47}$

$\text{ ( x - 103 )  + 47 = 120}$

$\text{x - 103 = 120 - 47}$

$\text{x - 103 = 73}$

$\text{x = 73 + 103}$

$\text{x = 176}$

$\text{d) 1360 + ( 498 - x ) = 1378 + 122}$

$\text{1360 + ( 498 - x ) = 1500}$

$\text{498 - x = 1500 - 1360}$

$\text{498 - x = 140}$

$\text{x = 498 - 140}$

$\text{x = 358}$

#Chúc cậu học tốt ><