(a) Express c in terms of k.
Solution:
x^2 + x + c = 0
k^2 + k + c = 0
c = -k^2 - k
(b) Find the other root of the equation in (a).
How to do so? And explain the steps clearly. Thanks a lot.
更新1:
root one +root two = - b/a root one x root two = c/a I just find this two principles to solve this equation How come?
更新2:
they are related to product of roots and sum of roots They are Chapter 2 in my maths book but the question is in Chapter 1
更新3:
Hence, I can just only solve the quadratic equation by factor method, quadratic formula, graphical method
更新4:
Sol: For the curve x^2 + x + c = 0 By using Quadratic formula, - 1 ± √[1-4(1)(c)] / 2(1) =- 1 ± √[1-4(-k^2 - k) / 2 =- 1 ± √(1+4k^2 +4k) / 2 =- 1 ± √(2k+1)^2 / 2 =- 1 + (2k+1) / 2 or - 1 - (2k+1) / 2 = k or -k - 1 The other root is - k - 1