Răspuns :
x+3(1+3+...+3⁹⁸)=x+3(3⁹⁹-1)/(3-1)= x+(3¹⁰⁰-3)/2
Acum
x+(3¹⁰⁰-3)/2=(3¹⁰⁰-1)/2
x-3/2=-1/2
x==3/1-1/2=2/2=1
Raspuns: x=1
Răspuns:
x = 1
Explicație pas cu pas:
Folosim formula
Sn = b₁(qⁿ - 1)/(q - 1)
x + 3 + 3² + .. +3⁹⁹ = (3¹⁰⁰ - 1)/2
x + 3(3⁹⁹ - 1)/(3 - 1) = (3¹⁰⁰ - 1)/2
x + (3¹⁰⁰ - 3)/2 = (3¹⁰⁰ - 1)/2
x = (3¹⁰⁰ - 1)/2 - (3¹⁰⁰ - 3)/2
x = (3¹⁰⁰ - 1 - 3¹⁰⁰ + 3)/2
x = (3 - 1)/2
x = 2/2
x = 1