4/15=12/45

1+2+3+4+5+...+x=465

(x+1)x:2=465

x(x+1)=465.2

x(x+1)=930

x(x+1)=2.3.5.31

x(x+1)=30.31

=>x=30.

2952:[151-(15x-2)]=24

<=>151-(15x-2)= 2952: 24

<=>151-(15x-2) =123

<=>15x-2= 151-123

<=>15x-2= 28

<=>15x= 28+2

<=>15x= 30

<=>x= 30: 15

<=>=2

Vậy x=2

x=3

2/5=14/35

3/7=15/35

lx

Anna một lần nữa

B

2:B

3:C

4:C

5:A

6:A

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