Réitigh 325=n[8b+(n-1)*(-3)/2

$$325 = \frac { n [ 8 b + ( n - 1 ) \times ( - 3 ) } { 2 }$$

Réitigh do b.

$$b=\frac{3n}{8}-\frac{3}{8}+\frac{325}{4n}$$

$$n\neq 0$$

Céimeanna chun Cothromóidí Líneacha a Réiteach

Iolraigh an dá thaobh faoi 2.

$$325\times 2=n\left(8b+\left(n-1\right)\times \left(-3\right)\right)$$

Méadaigh 325 agus 2 chun 650 a fháil.

$$650=n\left(8b+\left(n-1\right)\times \left(-3\right)\right)$$

Úsáid an t-airí dáileach chun n a mhéadú faoi 8b+\left(n-1\right)\times \left(-3\right).

$$650=8nb+n\left(\left(n-1\right)\times \left(-3\right)\right)$$

Athraigh na taobhanna ionas go mbeidh na téarmaí inathraitheacha ar fad ar an taobh clé.

$$8nb+n\left(\left(n-1\right)\times \left(-3\right)\right)=650$$

Bain n\left(\left(n-1\right)\times \left(-3\right)\right) ón dá thaobh.

$$8nb=650-n\left(\left(n-1\right)\times \left(-3\right)\right)$$

Athordaigh na téarmaí.

$$8bn=-n\left(\left(n-1\right)\times \left(-3\right)\right)+650$$

Tá an chothromóid i bhfoirm chaighdeánach.

$$8nb=3n\left(n-1\right)+650$$

Roinn an dá thaobh faoi 8n.

$$\frac{8nb}{8n}=\frac{3n\left(n-1\right)+650}{8n}$$

Má roinntear é faoi 8n cuirtear an iolrúchán faoi 8n ar ceal.

$$b=\frac{3n\left(n-1\right)+650}{8n}$$

Roinn 3\left(n-1\right)n+650 faoi 8n.

$$b=\frac{3n}{8}-\frac{3}{8}+\frac{325}{4n}$$

Réitigh do n.

$$n=-\frac{\sqrt{64b^{2}+48b-7791}}{6}+\frac{4b}{3}+\frac{1}{2}$$

$$n=\frac{\sqrt{64b^{2}+48b-7791}}{6}+\frac{4b}{3}+\frac{1}{2}\text{, }b\geq \frac{5\sqrt{78}}{4}-\frac{3}{8}\text{ or }b\leq -\frac{5\sqrt{78}}{4}-\frac{3}{8}$$