Question

aratati ca a=(1+2+3+...+50)-25x4 este patrat perfect si calculati radical din a
URGENTTTTTTTTTTTTTTT

Answer 1

Salutare!

$\bf a=(1+2+3+...+50)-25\cdot4$

$\bf a=\dfrac{(50+1)\cdot 50}{2} -25\cdot4$

$\bf a=\dfrac{51\cdot 50}{2} -100$

$\bf a=\dfrac{51\cdot \not50}{\not 2} -100$

$\bf a=\dfrac{51\cdot 25}{1} -100$

$\bf a=51\cdot 25 -100$

$\bf a=1275 -100$

$\bf a=1175$

$\bf a=5^{2} \cdot 47\implies \text{\bf nu este patrat perfect}$

$\bf a=\sqrt{5^{2} \cdot 47} \implies \boxed{\bf a= 5\sqrt{47} }$

==pav38==