y=9/5(x-40)^3+30 eching

$$y = \frac { 9 } { 5 } ( x - 40 ) ^ { 3 } + 30$$

y uchun yechish

$$y=\frac{9\left(x-40\right)^{3}}{5}+30$$

Yechim qadamlari

\left(a-b\right)^{3}=a^{3}-3a^{2}b+3ab^{2}-b^{3} binom teoremasini \left(x-40\right)^{3} kengaytirilishi uchun ishlating.

$$y=\frac{9}{5}\left(x^{3}-120x^{2}+4800x-64000\right)+30$$

\frac{9}{5} ga x^{3}-120x^{2}+4800x-64000 ni ko'paytirish orqali distributiv xususiyatdan foydalanish.

$$y=\frac{9}{5}x^{3}-216x^{2}+8640x-115200+30$$

-115170 olish uchun -115200 va 30'ni qo'shing.

$$y=\frac{9}{5}x^{3}-216x^{2}+8640x-115170$$

x uchun yechish

$$x=\frac{\sqrt[3]{15\left(y-30\right)}+120}{3}$$