7. A garden measuring 12 metres by 16 metres is to have a path installed all around it, increasing the total area to 285 square metres.
(i) Write down an expression for the length and the width of the garden, including the path.
(ii) Write an equation, in terms of x, for the area of the entire garden (including the path).
(iii) Find the width of the path.
8. Cathal throws a stone upward from a bridge over a river. The height of the stone above the river (measured in metres) t seconds after Cathal throws it is h(t) = −5t2
+ 10t + 15
(i) What is the height of the stone two seconds after Cathal throws it? (ii) How long does it take for the stone to hit the river?
9. Sarah is standing at the top of a cliff 1680 m high and launches a rocket upwards. Exactly t seconds after Sarah launches the rocket, its height (in metres) is h(t) = 16t2
+ 256t + 1680 (i) Find h when t = 3
(ii) How far does the rocket travel during the two seconds between 5 seconds and 7 seconds after Sarah launches it?
(iii) How long does it take for the rocket to reach a height of 2640 metres? Give your answer correct to two decimal places.
10. The area of a rectangle is 1260 m2 . One side of the rectangle is 48 m longer than three times the
other side. Find the length of the two sides of the rectangle.