Question

a.Determinati 6 multiplii consecutivi a lui 5 stiind ca suma lir este 165.
b.Determinati 4 multipli consecutivi a lui 7, stiind ca suma lor este egala cu 154.

Answer 1

5x+5(x+1)+5(x+2)+5(x+3)+5(x+4)+5(x+5)=165
5x+5x+5+5x+10+5x+15+5x+20+5x+25=165
30x+75=165
30x=165-75
30x=90
x=90/30
x=3
deci numerele sunt :15, 20, 25, 30, 35, 40

7x+7(x+1)+7(x+2)+7(x+3)=154
7x+7x+7+7x+14+7x+21=154
28x+42=154
28x=154-42
28x=112
x=112/28
x=4
numerele sunt: 28, 35, 42, 49