390=5*30+30left(30-1right)/2d eching

$$390 = 5 \cdot 30+ \frac{ 30 \left( 30-1 \right) }{ 2 } d$$

d uchun yechish

$$d=\frac{16}{29}\approx 0,551724138$$

Chiziqli tenglamalarni yechish bo'yicha qadamlar

Tenglamaning ikkala tarafini 2 ga ko'paytirish.

$$780=10\times 30+30\left(30-1\right)d$$

300 hosil qilish uchun 10 va 30 ni ko'paytirish.

$$780=300+30\left(30-1\right)d$$

29 olish uchun 30 dan 1 ni ayirish.

$$780=300+30\times 29d$$

870 hosil qilish uchun 30 va 29 ni ko'paytirish.

$$780=300+870d$$

Tomonlarni almashtirib, barcha oʻzgaruvchi shartlar chap tomonga oʻtkazing.

$$300+870d=780$$

Ikkala tarafdan 300 ni ayirish.

$$870d=780-300$$

480 olish uchun 780 dan 300 ni ayirish.

$$870d=480$$

Ikki tarafini 870 ga bo‘ling.

$$d=\frac{480}{870}$$

\frac{480}{870} ulushini 30 ni chiqarib, bekor qilish hisobiga eng past shartlarga kamaytiring.

$$d=\frac{16}{29}$$