The length of a rectangle is 6 cm more than the breadth. If the perimeter of rectangle is 80 cm , find the leng th and the beradth of the rectrople

4 Nella funzione \( f(x)=2 x^{3}+k x^{2}+\frac{x}{3}-3 \) è \( f(1)=\frac{7}{3} \). Trova \( k \).

Resolve into partial fractions: a) \( \frac{5 x+2}{3 \mathbf{x}^{2}+4 x-4} \)

21. If \( (2.4)^{x}=\left(0.2^{2}\right) \) \( \begin{array}{ll}\text { 22. If } 2^{x}=4^{y}=8^{z} \text { and } x y z=288 \text {, then } \frac{1}{2 x}+\frac{1}{4 y}+\frac{1}{8 z} \text { equals } \\ \begin{array}{lll}\text { (a) } \frac{11}{8} & \text { (b) } \frac{11}{24} & \text { (c) } \frac{11}{48}\end{array}\end{array} \)

27. If \( 2^{\prime \prime}=4^{\prime}=8^{\prime} \) and \( x y z=288 \), then \( \frac{1}{2 x}+\frac{1}{4 y}+\frac{1}{8 z} \) equals \( \begin{array}{llll}\text { (a) } \frac{11}{8} & \text { (b) } \frac{11}{24} & \text { (c) } \frac{11}{48} & \text { (d) } \frac{11}{96}\end{array} \)

(3) Determine the domain for which the functions \( f(x)=2 \mathrm{x}^{2}-1 \) and \( g(x)=1-3 x \) are equal. Solution: