For the equation x^2 - 2x - 8 = y find: (a) The roots. (b) The y-intercept. (c) The coordinate of the turning point

(a) Several methods to do this, simplest would be to factorise the quadratic into (x - 4)(x + 2) = 0 and from here see that root occur at x = 4 and x = -2.(b) Substitute x = 0 into the equation 0^2 - 20 - 8 = - 8 = y, so y-intercept at y = -8.(c) Quadratic equations are symmetrical so the x coordinate of the tuning point occurs midway between the 2 roots so x = 1, substitute this into the equation to get out y = 1^2 - 12 - 8 = -9, so the coordinate of the tuning point is (1,-9).

BC
Answered by Benjamin C. Maths tutor

4922 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How do you factorise x^2 +5x+6?


Vectors a and b are defined by a = 2i + 3j and b = 4i - 2j, find 3a-b in terms of i and j


Mixed rugby team of 20, 5 are female. 15 play at a time. i.) What is the percentage chance of a female playing. ii.)A minimum of three females must now be on the pitch. What is the percentage chance of 4 females playing?


If x:y = 7:4 and x+y = 88 , work out the value of x–y.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning