Question

1+x+2+x+3+x+•••+20+x=2009
VA ROG AJUTATIMA!

Answer 1

X.(1+2+3+...20)=2009 
x.(20.21):2=2009
De aici te descurci!

Answer 2

[tex]\it 1+x+2+x+3+x+\ ...\ +20+x=2009 \\\;\\ (1+x)+(2+x)+(3+x)+\ ...\ +(20+x)=2009 \\\;\\ (1+2+3+\ ...\ +20) +20x = 2009 [/tex]

[tex]\it \dfrac{20\cdot21}{2} +20x=2009 \Rightarrow 210+20x=2009|_{210} \Rightarrow 20x=1799 \Rightarrow \\\;\\ \Rightarrow x = \dfrac{1799}{20} \Rightarrow x =89,95 [/tex]