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

19 days of March 2015 . \( \begin{array}{llll}\text { (1) } ₹ 1530 & \text { (2) } ₹ 1260 & \text { (3) } ₹ 1620 & \text { (4) } ₹ 1710\end{array} \) \( x \propto \frac{1}{y} \). When \( y=6, x=14 \). What is the constant of variation ? \( \begin{array}{llll}\text { (1) } 94 & \text { (2) } 84 & \text { (3) } 82 & \text { (4) } 72\end{array} \) If \( x \) varies directly as \( y \), which number will replace the question

(c) Subtract: \( 31(1-4 m+5 n) \) from \( 4 I(10 n-3 m+21) \) (d) Subtract: \( 3 a(a+b+c)-2 b(a-b+c) \) from \( 4 c(-a+b+c \)

Simplify the expression: \( (x^{1/4}y^{1/2})^{8} \)

\( \frac { 1 } { r } x \frac { 1 - ( \frac { 1 } { r } ) ^ { n } } { 1 - \frac { 1 } { r } } \geq \frac { 9 r } { 100 } \Rightarrow 1 - \frac { 1 } { r ^ { n } } \geq \frac { 9 r } { 100 } \)

3. ( 0,5 điểm) Tìm \( x \) biết: \( x^{2}(x-1)+4=4 x \)