Question

Answer 1

1: =>x-18=13

=>x=31

2: =>73-x=87-20=67

=>x=6

3: =>x-5=15

=>x=20

4: =>(x+2)^2:3=3

=>(x+2)^2=9

=>x+2=3 hoặc x+2=-3

=>x=1 hoặc x=-5

5: =>2(x-1)^2=18

=>(x-1)^2=9

=>x-1=3 hoặc x-1=-3

=>x=-2 hoặc x=4

6: =>3^x(1/3+1+3)=39

=>3^x=9

=>x=2

Answer 2

1) (x+7)-25=3

=> x + 7= 13+25

=> x + 7= 38

x = 38 - 7

x = 31

2) 87 - ( 73 - x ) = 20

=> 73 - x=87-20

=> 73-x=67

x=73-67

x=6

3) x-105:21=15

=> x-105=15.21

=>x-105=315

x=315+105

x=420

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