Question

tìm X <- N biết

( x + 2 ) + ( x + 4 ) + ( x + 6 ) + ... + ( x + 50 ) = 725

Answer 1

( x + 2 ) + ( x + 4 ) + ( x + 6 ) + ... + ( x + 50 ) = 725

<=> 25x + (2 + 4 + 6 + ..... + 50) = 725

<=> 25x + 650 = 725

=> 25x = 725 - 650

=> 25x = 75

=> x = 75 : 25

=> x = 3

Answer 2

25x+650=725

=>25x=725-650=75

=>x=75/25=3

t i c k cho mình nha