a) x + 2x + 3x + ................ + 100x = 5050
=> x.(1+2+3+4+...+100)=5050
=>x.\(\frac{\left(100-1+1\right).\left(100+1\right)}{2}\)= 5050
=>x.5050=5050
=> x = 1.
b) ( x + 2 ) + ( x + 4 ) + ( x + 6 ) + ......................+ ( x + 100 ) = 2650
=> 50x+(2+4+6+..+100)=2650
=>50x+\(\frac{\left[\left(100-2\right):2+1\right].\left(100+2\right)}{2}\)=2650
=>50x+2550=2650
=>50x=100
=>x=2
a) => x( 1+2+...+100) = 5050
=> 5050x = 5050
=> x = 1
Vậy x = 1
b) => (x+x+...+x) + (2+4+...+100) = 2650
=> 50x + 2550 = 2650
=> 50x =10
=> x = 1/5
Vậy x =1/5
