( x + x + x + ...+ x ) + ( 1 + 2 + 3 + ... + 10 ) = 385
x * 10 + 55 = 385
x * 10 = 385 - 55
x * 10 = 330
x = 330 : 10
x = 33
Vậy x = 33
(x + 1) + (x + 2) + (x + 3) +.....+(x + 10) = 385
=> 10x + (1 + 2 + 3 + 4 + ....+10) = 385
=> 10x + 55 = 385
=> 10x = 330
=> x = 33
\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+10\right)=385\)
\(\Rightarrow10x+\left(1+2+3+4+...+10\right)=385\)
\(\Rightarrow10x+\left(11.5\right)=385\)
\(\Rightarrow10x=385-55\)
\(\Rightarrow x=\frac{330}{10}=33\)
(x + 1) + (x + 2) + (x + 3) + ... + (x + 10) = 385
(x + x + x + ... + x) + (1 + 2 + 3 + ... + 10) = 385
10 số x 10 số hạng
10 × x + (1 + 10) × 10 : 2 = 385
10 × x + 11 × 5 = 385
10 × x + 55 = 385
10 × x = 385 - 55
10 × x = 330
x = 330 : 10
x = 33
( x + x + x + ...+ x ) + ( 1 + 2 + 3 + ... + 10 ) = 385
x * 10 + 55 = 385
x * 10 = 385 - 55
x * 10 = 330
x = 330 : 10
x = 33
Vậy x = 33
( x + x + x + ...+ x ) + ( 1 + 2 + 3 + ... + 10 ) = 385
x * 10 + 55 = 385
x * 10 = 385 - 55
x * 10 = 330
x = 330 : 10
x = 33
Vậy x = 33
7/5-X=12/10
