Question

rezolvati ecuatia: 2+7+12+17+…+x=198

Answer 1

Explicație pas cu pas:

Sn = (n/2) * (a1 + an)

Sn = (10/2) * (2 + x)

= 5 * (2 + x)

= 10 + 5x

Sn = n * (a1 + an) / 2

Sn = 10 * (2 + x) / 2

= 5 * (2 + x

10 + 5x = 198

5x = 188

x = 188 / 5

x = 37.6