What is the simplest form of the radical expression \( \sqrt{72 x^{5} y^{4}} ? \) Assume \( x \) and \( y \) are positive. \( 6 x y \sqrt{x y} \) \( 6 x y^{2} \sqrt{2 x} \) \( 6 x^{2} y^{2} \sqrt{2 x} \) \( 6 x y^{2} \sqrt{2 x y} \)

\( 4(x-5)=8 \) Solve the equation above for \( x \). Which of the following is the correct answer? \( 3 / 4 \) 7

Exercice 3 (9pts) : 1. a) Simplifier \( \quad E=\frac{a^{2} \times\left(b^{2} \times a^{3}\right)^{-2}}{\left(b^{-3}\right)^{2}} \)

3) Sofia drove her Car 45 kelometers and sheran out of gos and had to waik 2 kelometers to a gass station. tter spead af drivingts 15 times here speed of walking. If the total time for the drive and walk was \( 1 / 2 \) hours, What was sofia's driving speed?

5. Résoudre l'équation \( 25 x^{2}-81=0 \)

If \( x \) represents the width of a rectangle and the length is four less than three times the width, which of the following expressions represents the length of the rectangle in terms of \( x \) ? \( 3 x-4 \) \( 4-3 x \) \( 4 x-3 \)