Question

(4+8+٠٠٠٠٠+ 100):13​

Answer 1

Răspuns:

100

Explicație pas cu pas:

(4+8+٠٠٠٠٠+ 100):13​ = 4·(1+2+3+......+25) :13 =

= 4·(1+25)·25:2:13 = 4·26·25:2:13 = 4·25·(26:2:13) =

=4·25 = 100

Answer 2

 

$\displaystyle\bf\\(4+8+...+ 100):13=?\\\\Metoda~1:\\\\n=\frac{100-4}{4}+1=\frac{96}{4}+1=24+1=25~de~termeni\\\\(4+8+...+ 100):13=\frac{25(100+4)}{2}:13=\\\\=\frac{25\times104}{2}:13=25\times52:13=1300:13=\boxed{\bf100}\\\\\\Metoda 2:\\\\(4+8+...+ 100):13=4(1+2+...+25):13=\\\\4\times\frac{25(25+1)}{2}:13=4\times\frac{25\times26}{2}:13=\\\\=4\times25\times13:13 =4\times25\times1=\boxed{\bf100}$