Key features and models of graphs Problem set A Answers

y-intercept \((0,\,-10)\); zeros \(x=1\) and \(x=5\); vertex \((3,\,8)\); axis \(x=3\)

1. (a) \(y=-4\)
2. (b) \(y=2\)
3. (c) \(y=7\)

1. (a) 245
2. (b) 3

Asymptotes \(x=2\) and \(y=4\); x-intercept \((-2,\,0)\); y-intercept \((0,\,-4)\)

1. (a) Exponential: a constant ratio
2. (b) Quadratic: it rises, then falls
3. (c) Linear: a fixed charge and a constant rate

1. (a) 3.8 m
2. (b) 7.36 m
3. (c) The ball leaves the hand 2 m above the ground.

1. (a) 80 °C
2. (b) 18 °C
3. (c) 20.7 minutes

1. (a) \(a=180\)
2. (b) 7.2 lux
3. (c) Very close to the lamp the intensity is very large; it is never infinite.

1. (a) Linear: \(y=4x+3\); at \(x=10\) the depth is 43 cm
2. (b) Exponential: \(y=5\times2^x\); at \(x=7\) there are 640 cells

\(a=4\); x-intercept \((-0.75,\,0)\); y-intercept \((0,\,-1.5)\)

\(k=4,\ a=2,\ c=3\); \(y=131\)