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

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

Datrys ar gyfer y

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

Camau ar gyfer Datrys Hafaliad Llinol

Defnyddio'r theorem binomaidd \left(a-b\right)^{3}=a^{3}-3a^{2}b+3ab^{2}-b^{3} i ehangu'r \left(x-40\right)^{3}.

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

Defnyddio’r briodwedd ddosbarthu i luosi -\frac{9}{5} â x^{3}-120x^{2}+4800x-64000.

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

Adio 115200 a 30 i gael 115230.

$$-y=-\frac{9}{5}x^{3}+216x^{2}-8640x+115230$$

Mae'r hafaliad yn y ffurf safonol.

$$-y=-\frac{9x^{3}}{5}+216x^{2}-8640x+115230$$

Rhannu’r ddwy ochr â -1.

$$\frac{-y}{-1}=\frac{-\frac{9x^{3}}{5}+216x^{2}-8640x+115230}{-1}$$

Mae rhannu â -1 yn dad-wneud lluosi â -1.

$$y=\frac{-\frac{9x^{3}}{5}+216x^{2}-8640x+115230}{-1}$$

Rhannwch -\frac{9x^{3}}{5}+216x^{2}-8640x+115230 â -1.

$$y=\frac{9x^{3}}{5}-216x^{2}+8640x-115230$$

Datrys ar gyfer x (complex solution)

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

$$x=\frac{e^{\frac{4\pi i}{3}}\sqrt[3]{15\left(y+30\right)}+120}{3}$$

$$x=\frac{e^{\frac{2\pi i}{3}}\sqrt[3]{15\left(y+30\right)}+120}{3}$$

Datrys ar gyfer x

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