m 0.5 m 2,3 2.5 ? The graphs to the right illustrate a fountain shooting a jet of water with a laser beam illuminating the jet in two places, one of them being (2 m,3 m). Determine the height of the other point illuminated by the laser. Equation of the jet of water Solution of the system The height of the other point illuminated by water is 1.75 meters. x 1 = 0.5; x 1 = 2.5; (x,y) = (2,3) y = a(x – x 1 )(x – x 2 ) 3 = a(2 – 0.5)( 2 – 2.5) 3 = a(1.5)(-0.5) 3 = -0.75a a = -4 y = -4(x – 0.5)(x – 2.5) y = -4(x 2 – 2.5x – 0.5x ) y = -4x x – 5 Equation of the laser beam x + 1 = -4x x – 5 4x x + x = 0 4x x + 6 = 0 4x 2 - 3x - 8x + 6 = 0 x(4x – 3) – 2(4x – 3) = 0 (4x – 3)(x – 2) = 0 4x – 3 = 0 OR x – 2 = 0

The proportion of men to women employed by a company has varied over the years of operation. The number of men was 428 in the year 2000 and reached a maximum of 500 three years later following a second degree curve. The number of women in 2000 was 100 and increased at a rate of 25 per years after that. men women year # of employees x: number of years after 2000 y: number of employees If the trends continue, in what year will the number of men and women be the same? How many will be employed by the company at that time? m = 25; b = 100 y = 25x Equation for women Equation for men Vertex: (3,500); Other point: (0,428) y = a(x – h) 2 + k 428 = a(0 – 3) – 500 = 9a 9a = -72 a = -8 y = -8(x – 3) y = -8(x 2 – 6x + 9) y = -8x x y = -8x x x = -8x x x x + 25x – = 0 8x x – 328 = 0 8x x + 41x – 328 = 0 8x(x – 8) + 41(x – 8) = 0 (x – 8)(8x + 41) = 0 x – 8 = 0 OR 8x + 41 = 0 x = 8 OR x = Solution of the System y = 25x y = 25(8) = = 300 employees After 8 years, there were 300 men and 300 women employed for a total of 600 employees

A cold front sweeps into the town of Amos causing the temperatures to drop steadily from 1°C at 2h to -4°C at 21h and continue. As yet unaffected by this cold front, on the same day Gaspe experiences temperatures indicated in the table to the right °C 0.4°C 2.4°C 3.6°C 4°C 3.6°C GASPE TimeTemp For how long is the temperature of Gaspe warmer than that of Amos during that time? x = time y = temperature Equation for Amos Solution of the System Vertex: (20,4); Other point: (8, 0.4) y = a(x – h) 2 + k 0.4 = a(8 – 20) – 4 = 144a 144a = -3.6 a = y = (x – 20) y = (x 2 – 40x + 400) + 4 y = x 2 + x y = x 2 + x - 6 Equation for Gaspe 0.475x x – 5x = x x = 0 a = 0.475; b = -24; c = 143 Δ = b 2 – 4ac = (-24) 2 – 4(0.475)(143) = 476 – =304.3 Gaspe was warmer than Amos between 6.91 hours and 43.6 hours: 43.6 – 6.9 = 36.1 hours.

A display is constructed to take pictures of kids with Santa Claus. Two symmetrical braces extend up from the floor to support the seat and attach to a piece of board above the seat. The display is 2.25 meters high and 1.5 meters wide at its base. The braces are 42 cm apart at the floor and 58 cm apart at the seat which is 48 cm above the floor. How long are the braces? How far apart are the braces at the top where they attach to the piece of board? x 2.25 m 1.5 m 42cm ? y seat braces Equation of the brace Vertex: (0, 2.25); Other point: (0.75, 0) y = a(x – h) 2 + k 0 = a(0.75 – 0) – 2.25 = a a = a = -4 y = -4x Equation of the parabola Solution of the System 6x – 1.26 = -4x x 2 + 6x = 0 a = 4; b = 6; c = Δ = b 2 – 4ac = 6 2 – 4(4)(-3.51) = = y = 6x – 1.26 = 6(0.45) – 1.26 = 2.7 – 1.26 = 1.44

End points of right brace: (0.21,0); (0.45,1.44) x 2.25 m 1.5 m 42cm ? y seat braces (0.21,0) (0.45,1.44) Length of right brace: (x 1, y 1 ) = (0.21,0); (x 2, y 2 ) = (0.45,1.44) x 2.25 m 1.5 m 42cm ? y seat braces (-0.45,1.44) (0.45,1.44) Length of right brace: =|0.45-(-0.45)| =0.9 m End points of right brace: (-0.45,1.44); (0.45,1.44)

A new business is starting and the manager is analyzing his expenses and revenues. The monthly expenses start at $1950 and increase to a maximum of $2550 after 5 months at which point the expenses start to decline. The revenues increase at a constant rate of $30 per month and reach $2256 after 12 months. At what point will there be a zero deficit? ( i.e. revenue = expenses) expenses revenue month $ m = 30; ( x 1, y 1 ) = (12,2256) Equation for revenueEquation for expenses Vertex: (5,2550); Other point: (0,1950) y = a(x – h) 2 + k 1950 = a(0 – 5) – 2550 = 25a 25a = -600 a = -24 y = -24(x – 5) y = -24(x x + 25) y = -24x x y = -24x x Solution of the System 30x = -24x x x x + 30x – = 0 24x x – 54 = 0 4x x – 9 = 0 4x 2 + 1x - 36x – 9 = 0 x(4x + 1) – 9(4x + 1) = 0 (4x + 1)(x – 9) = 0 4x + 1 = 0 OR x - 9 = 0 x = OR x = 9 There is a zero deficit after 9 months.

Plans for a highway indicate that it will cross a river in 2 places. Use the coordinates from the graph provided to determine the length of the section of the highway to be built between the bridges. (9,4.2) E N (5,1) 1 unit = 1 km River Highway Bridges Equation for Highway Equation for River Vertex: (5,1); Other point: (9,4.2) y = a(x – h) 2 + k 4.2 = a(9 – 5) = 16a 16a = 3.2 a = 0.2 y = 0.2(x – 5) y =0.2(x 2 – 10x + 25) + 1 y = 0.2x 2 – 2x y = 0.2x 2 – 2x + 6 Solution of the System 0.2x 2 – 2x + 6 = 0.4x x 2 – 2x – 0.4x + 11 – 0.6 = 0 0.2x 2 – 2.4x = 0 x 2 – 12x + 27 = 0 (x – 3)(x – 9) = 0 x – 3 = 0 OR x – 9 = 0 x = 3 OR x = 9 y = 0.4(3) = = 1.8 (3, 1.8) y = 0.4(9) = = 4.2 (9, 4.2)