Question

Determinati numarul narural "x",daca:

4+8+12+...+396=200x

Answer 1

$4+8+12+...+396=200x \ |:4 \ \ \ (Se \ imparte \ toata \ expresia \ prin \ 4)\\\\ 1+2+3+...+99=50x \\\\ \frac{(1+99)}{2}*99=50x \\\\ \frac{100}{2}*99=50x \\\\ 50*99=50*x \\\\ \boxed{x=99}$

Answer 2

4+8+12+...+396=200x     :4
1+2+3+....+99=50x
99x100/2=9900/2=4950
4950=50x
x=4950/50=99