Question

1+2+3+.........+50+x=2x+2+4+6+.........30
x=???????.????????dau coroană​

Answer 1

Răspuns:

Explicație pas cu pas:

1+2+3+......+50 + x = 2x + 2+4+6+......+ 30

2x + 2×(1+2+3+....+15) = 50×(1+50):2+x

2x + 2×15×16/2 = 25×51 + x

2x + 240 = 1275 + x

2x - x = 1275 - 240

x = 1 035