Câu b,
= 50x + (1 + 3 + 5 + ..... + 99) = 2550
= 50x + 2500 = 2550
= 50x = 2550 - 2500
= 50x = 50
= x = 50 : 50
= x = 1
refer
A) 2448:[119-[x-6]]=24
<=> 199 - ( x-6 ) = 2448 : 24 = 102
<=> x - 6 = 199 - 102 = 97
<=> x = 97 +6 = 103
B) (x+1)+(x+3)+(x+5)+......+(x+99) = 2550
(x+x+x+....+x)+(1+3+5+....+99) = 2550
50x + 2500 = 2550
50x = 2550 - 2500
50x = 50
x = 50 : 50
x = 1