a) (x + 1) + (x + 2) + (x + 3) + ... + (x + 9) = 54
(x + x + x + ... + x) + (1 + 2 + 3 + ... + 9) = 54
9x + 45 = 54
9x = 54 - 45
9x = 9
x = 1
b) (x + 1) + (x + 2) + (x + 3) + ... + (x + 10) = 2010
(x + x + x + ... + x) + (1 + 2 + 3 + ... + 10) = 2010
10x + 55 = 2010
10x = 2010 - 55
10x = 1955
x = 391/2.
1)\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+....+\left(x+9\right)=54\)
\(\Rightarrow x+1+x+2+x+3+.....+x+9=54\)
\(\Rightarrow\left(x+x+x+....+x\right)+\left(1+2+3+....+9\right)=54\)
\(\Rightarrow9x+45=54\)\(\Rightarrow9x=9\Rightarrow x=1\)
2)\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+....+\left(x+10\right)=2010\)
\(\Rightarrow x+1+x+2+x+3+.....+x+10=2010\)
\(\Rightarrow\left(x+x+x+....+x\right)+\left(1+2+3+....+10\right)=2010\)
\(\Rightarrow10x+55=2010\Rightarrow10x=1995\Rightarrow x=195,5\)