Datrys {l}{f(x)=-x^2+3x+5}{x=-5/3}

$$\left. \begin{array} { l } { f ( x ) = - x ^ { 2 } + 3 x + 5 } \\ { x = - \frac { 5 } { 3 } } \end{array} \right.$$

Datrys ar gyfer f, x

$$x = -\frac{5}{3} = -1\frac{2}{3} \approx -1.666666667$$

$$f = \frac{5}{3} = 1\frac{2}{3} \approx 1.666666667$$

Camau Ateb

Ystyriwch yr hafaliad cyntaf. Mewnosod y gwerthoedd sy’n hysbys i’r hafaliad.

$$f\left(-\frac{5}{3}\right)=-\left(-\frac{5}{3}\right)^{2}+3\left(-\frac{5}{3}\right)+5$$

Cyfrifo -\frac{5}{3} i bŵer 2 a chael \frac{25}{9}.

$$f\left(-\frac{5}{3}\right)=-\frac{25}{9}+3\left(-\frac{5}{3}\right)+5$$

Lluosi 3 a -\frac{5}{3} i gael -5.

$$f\left(-\frac{5}{3}\right)=-\frac{25}{9}-5+5$$

Tynnu 5 o -\frac{25}{9} i gael -\frac{70}{9}.

$$f\left(-\frac{5}{3}\right)=-\frac{70}{9}+5$$

Adio -\frac{70}{9} a 5 i gael -\frac{25}{9}.

$$f\left(-\frac{5}{3}\right)=-\frac{25}{9}$$

Lluoswch y ddwy ochr â -\frac{3}{5}, cilyddol -\frac{5}{3}.

$$f=-\frac{25}{9}\left(-\frac{3}{5}\right)$$

Lluosi -\frac{25}{9} a -\frac{3}{5} i gael \frac{5}{3}.

$$f=\frac{5}{3}$$

Mae’r system wedi’i datrys nawr.

$$f=\frac{5}{3} x=-\frac{5}{3}$$