19. \( x^{2}-9 x+9<0 \)

Calcule os determinantes a seguir: \[ \begin{array}{lll}3 & 2 & 1 \\ 2 & 4 & 3 \\ 1 & 5 & 2\end{array}|\quad| \begin{array}{cc}2 & 6 \\ -1 & 3 \\ 3 & 4\end{array} \]

Find the area of the surface in the first octant cut from the cylinder \( y=\frac{2}{3} z^{3 / 2} \) by the planes \( x=1 \) and \( y=\frac{2}{3} \). The surface area is (Type an exact answer, using radicals as needed.)

Réaliser: A l'aide des points du tableau question 1, représenter ces 3 fonctions dans le même repère:

Find the first term, \( a_{1} \), of the geometric series given \( S_{7}=635, r=2 \), and \( n=7 \). Remember to use the formula \( S_{n}=\frac{a_{1}\left(1-r^{n}\right)}{1-r} \)

a) \( 8 x^{2}+8 x+16 \)