Solving and forming polynomial equations Problem set B Answers

1. (a) x = −6.19 or −0.807
2. (b) x = −0.167 (a repeated root)
3. (c) No real roots

1. (a) x = −2.60, 0.340 or 2.26
2. (b) x = −1.34

1. (a) x = −2.48, −1, 0.552 or 2.93
2. (b) x = −1.32 or 0.712

1. (a) x = −1.31 or 3.81
2. (b) x = −1.83, −0.657 or 2.49

6 cm

r = −1.4 or 0.4

1. (a) \(2x^2 - 24x - 27=0\)
2. (b) x = 13.0; the other solution, x = −1.04, is negative

1. (a) \(x^2+21x-40=0\)
2. (b) x = 1.76 m

1. (a) \(4x^3 - 156x^2 + 1440x - 3000=0\)
2. (b) x = 2.96 or 9.57

5.82 cm

1. (a) \(h=\frac{120-\pi r^2}{\pi r}\)
2. (b) \(\pi r^3-120r+250=0\)
3. (c) r = 2.49 or 4.55

n = 21

729 and 1000, or −1000 and −729

1. (a) \(\frac{n(n-3)}{2}\)
2. (b) n = 12