Question

Rezolvati ecuatia:
x la a doua +25=2+4+6+....+50

Answer 1

2+4+6+...+50 este suma termenilor unei progresii aritmetice cu ratia 2
2+4+...+50=(2+50)25/2=25x26=650
x²+25=650
x²=625
x1=√625=25
x2=-25

Answer 2

x^2+25=2+4+6+...+50
x^2+25=2(1+2+3+...+25)
x^2+25=2[(1+25)•25/2]
x^2+25=2[26•25/2]
x^2+25=25•26
x^2=25•26-25
x^2=25•25
x=√625=+25 sau -25