Question

1 + 3 + 5 + .... + ( 2x - 1 ) = 225

Ai làm xong trước mk tick!

Answer 1

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khó vlllll

Answer 2

1+3+5+...+(2x-1)=225=[(1+2x-1)x]:2=x²

ta có x²=225

x²=3².5²=(15)²=>x=15

Answer 3

1+3+5+...+(2x - 1) = 225

(1+( 2x- 1 ) ) * x /2 = 225

2x * x / 2 = 225 

( 2/2 ) * (x * x) = 225

1*x² = 225

x²  =15²

=> x = 15