Read the following description of a relationship: \[ \begin{array}{l}\text { Whitney has a superhero lunch box collection with } 20 \text { lunch boxes in it. From } \\ \text { now on, she decides to buy one new lunch box every year for her birthday. } \\ \text { Let } y \text { represent the number of years from now and } b \text { represent the total number } \\ \text { of lunch boxes in her collection. }\end{array} \] Use the function \( b=y+20 \) to find the value of \( b \) when \( y=1 \). \( b=\square \)

\( 2 ( x + 5 ) \cdot 7 = 3 ( x - 2 ) \quad \{ x - 3 , x = 3 , x = 1 \)

9. Show that (i) \( \binom{n+2}{2}-\binom{n}{2}=n+\frac{1}{2} \) Solution:

\( 6 x^{3}-5 x^{7}+6 \) leading term? Leading cafficient? Turning Caint?

76. Решите графически систему линейных уравнений: \( \begin{array}{ll}\text { а) }\left\{\begin{array}{l}x-y=1, \\ x+3 y=9 ;\end{array}\right. & \text { в) }\left\{\begin{array}{l}x+y=0, \\ -3 x+4 y=14 ;\end{array}\right. \\ \text { б) }\left\{\begin{array}{ll}x+2 y=4, \\ -2 x+5 y=10 ; & \text { г) }\left\{\begin{array}{l}3 x-2 y=6, \\ 3 x+10 y=-12\end{array}\right.\end{array}\right.\end{array} \).

Find the factar of \( x^{5}+x^{4}-13 x^{3}-13 x^{2}+36 x+36 \) ai list three factars.