\(\text{(x+1)+(x+2)+(x+3)+(x+4)+(x+5)+(x+6)+(x+7)+(x+8)+(x+9)=54}\)
\(\text{x+1+x+2+x+3+x+4+x+5+x+6+x+7+x+8+x+9=54}\)
\(9x+\left(1+2+3+4+5+6+7+8+9\right)=54\)
\(9x-45=54\)
\(9x=99\)
\(x=11\)
\(\text{(x+1)+(x+2)+(x+3)+(x+4)+(x+5)+(x+6)+(x+7)+(x+8)+(x+9)=54}\)
\(\text{x+1+x+2+x+3+x+4+x+5+x+6+x+7+x+8+x+9=54}\)
\(\text{9x + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 54 }\)
\(\text{9x − 45 = 54 }\)
\(\text{9x = 99 }\)
\(\text{x = 11}\)
(x+x+x+x+x+x+x+x+x) + (1+2+3+4+5+6+7+8+9)=54
x.9+ (9+1)+(2+8)+(3+7)+(4+6)+5 =54
x.9+45 =54
x.9 =54-45
x.9 =9
x =9:9
x=1