( x + 1 ) + ( x + 3 ) + ........+ ( x+ 99 ) = 0
( x + x + ... + x ) + ( 1 + 3 + ... + 99 ) = 0
50x + 2500 = 0
50x = -2500
x = -2500 : 50
x = -50
x + ( x + 1 ) + ( x + 2 ) + ... + ( x + 30 ) = 1240
( x + x + x + ... + x ) + ( 1 + 2 + ... + 30 ) = 1240
31x + 465 = 1240
31x = 1240 - 465
31x = 775
x = 775 : 31
x = 25
x + ( x+1) + (x+2) + ( x+3) +...+ (x+30)= 1240
x+(x+1)+(x+2)+(x+3)+........+(x+30)=1240
x+(x+1)+(x+2)+(x+3)+.....+(x+30)=1240
x+(x+1)+(x+2)+(x+3)+.....+(x+30) = 1240
Tìm x:
a)39.(5-2x)=39
b)x+(x+1)+(x+3)+...+(x+99)=1240
c) (x+1)+(x+3)+...+(x+99)=7500
d)1+2+3+...+100=1/2.x(x+1). (x thuộc N)
a) x + (x + 1) + (x + 2) + (x+3)+...+(x + 30) = 1240
b) x + 1 + 2 + 3 + ... + x = 210
x+( x+1)+(x+2)+(x+3)+.......+(x+30)=1240
Tìm x, biết:
a) x+(x+1)+(x+2)+(x+3)+...+(x+30)=1240
b) 1+2+3+...+x=210
tìm x thuộc N biết:
a)x+(x+1)+(x+2)+(x+30)+...+(x+30)=1240
b)1+2+3+...+x=210
