(b) Jika a lalah sebutan pertama dan \( r \) ialah nisbah sepunya bagi suata janjang geometri, tunjukkan bahawa hasil tambah \( n \) sebutan pertama bagi janjung itu ialah If \( a \) is the first term and \( r \) is the common ratio of a geometric progression, show that the sum of the first \( n \) terms of the prognession is \[ S_{n}=\frac{a\left(r^{3}-1\right)}{r-1} \] [3 mariah]

\( \begin{array}{ll} & \text { Solve for } x: \\ 2.1 & (x-5)(x+3)=0 \\ 2.2 & 2^{x-1}=10-2^{x+1} \\ 2.3 & 5^{3 x-6}=125 \\ 2.4 & \frac{x^{2}-3}{2}=x\end{array} \)

प्रश्नाबानी 2.2 निम्न द्विघात बहुपदों के शून्यक ज्ञात कीजिए और शून्यकों तथा गुणांकों के बीच के संबंध की सत्यता की जाँच कीजिए : \( \begin{array}{lll}\text { (iv) } x^{2}-2 x-8 & \text { (ii) } 4 s^{2}-4 s+1 & \text { (iii) } 6 x^{2}-3-7 x \\ \text { (iv) } 4 u^{2}+8 u & \text { (v) } s^{2}-15 & \text { (vi) } 3 x^{2}-x-4\end{array} \)

Risolvi le seques \( \frac{-x^{2}+7 x-12}{2 x^{2}-7 x+3} \geqslant 0 \)

Find the slope and the \( y \)-intercept of the graph of the equation. \[ 8 x+9 y=36 \] slope \( y \)-intercept \( \quad(x, y)=(\square) \)

D) A student claimed that the largest integer of \( k \) for which the graph \( y=2 x^{2}-3 x+k-1 \) meets the \( x \)-axis is 2 . Verify this statement.