Question

Tìm x:

a) (3x-12) : 8 + 10 = 13

b) (x + 5).8-20 = 60

c) 3.[ 35 + (x-10) ] - 375 = 0

d) ( 158x+ 173 - 24 ) : 35 = 81

e) x - 140 : 35 =0

Answer 1

a) (3x-12) :8 +10= 13

<=> (3x-12):8 = 13-10 = 3

<=> 3x-12 = 3 .8 = 24

<=> 3x = 24+12=36

<=> x=36:3=12

b) (x+5).8-20 = 60

<=> (x+5) .8 = 60+20=80

<=> x+5 = 80:8 = 10

<=> x=10-5 = 5

c) 3.[35+(x-10)]-375 = 0

<=> 3.[35+(x-10)] = 0 +375=375

<=> 35+(x-10) = 375 :3 = 125

<=> x-10 = 125-35=90

<=> x = 90+10 = 100

d) ( 158x+173-24) :35 = 81

<=> 158x+149 = 81 . 35 = 2835

<=> 158x = 2835 -149= 2686

<=> x= 2686 : 158 = 17

e) x - 140 : 35 = 0

<=> x-4 = 0

<=> x=0+4 = 4

 

Answer 2

(3x - 12 ) : 8 + 10 = 13 

(3x - 12 ) : 8 = 13 - 10 = 3

(3x - 12 ) = 3 x 8 = 24

3x = 24 - 12 = 12

x =13 : 3 = 4

( x + 5 )