( 2 + x ) + ( 4 + x ) + ( 6 + x ) + ... + ( 52 + x ) = 780
2 + x + 4 + x + 6 + x + ... + 52 + x =780 ( đây là bước phá ngoặc )
( 2 + 4 + 6 + ... + 52 ) + ( x + x + x + ... + x ) ( có 26 số x) = 780
702 + 26.x = 780
26.x = 780 - 702 ( dấu chấm là dấu nhân nhé
26.x = 78
x = 78 : 26
x = 3
Vậy x = 3
( cho mình 1 t i c k nhé :))
2 CONG 4 CONG 6 CONG ........... CONG [ 2 x X] = 2550
A] X-1,25x4= 2,5 b] [ X CONG 1 ] CONG [ X CONG 2] CONG [ X CONG 3 CONG ] .............. CONG [ X CONG 20] = 750 C ] [ X CONG 1] CONG [X CONG 2 ] CONG [ X CONG 3 ] CONG ........... CONG [ X CONG 10] = 175
[ X 1 cong ] cong [ X 2 cong ] cong[ X3 cong] CONG .............. CONG 20 = 750
x cong 1 cong x cong 2 cong ...x cong 100 bang 5050
1 CONG 3 CONG 5 CONG .........CONG [ 2 x X CONG 1] = 169
C] [ 1 CONG 4 CONG 7 CONG ................. CONG 403 ] x [ 357357 x 468 - 468468 - 375
1 CONG 3 CONG 5 CONG CONG .......... CONG [ 2x X CONG 1] =169
1 CONG 2 CONG 3 CONG ........... CONG X = 210
1 CONG 3 CONG 5 CONG ............... CONG [ 2x X 1] CONG 169
