Solving and forming polynomial equations Problem set A Answers

1. (a) x = 0.394 or 7.61
2. (b) x = 0.6 (a repeated root)
3. (c) No real roots

1. (a) x = −2.33, 0.202 or 2.13
2. (b) x = −1.84

1. (a) x = −2.71, −0.536, 0.872 or 2.37
2. (b) x = −1.90 or 1.39

1. (a) x = −2.67 or 1
2. (b) x = −1.68, −0.539 or 2.21

7 cm

r = −1.5 or 0.5

1. (a) \(2x^2 - 16x - 12=0\)
2. (b) x = 8.69; the other solution, x = −0.690, is negative

1. (a) \(x^2+20x-30=0\)
2. (b) x = 1.40 m

1. (a) \(4x^3 - 120x^2 + 864x - 1500=0\)
2. (b) x = 2.58 or 7.17

5.18 cm

1. (a) \(h=\frac{150-\pi r^2}{\pi r}\)
2. (b) \(\pi r^3-150r+300=0\)
3. (c) r = 2.23 or 5.52

n = 24

512 and 729, or −729 and −512

1. (a) \(\frac{n(n-3)}{2}\)
2. (b) n = 11