Target Mathematics

3.101: Completing the square, sketch and inequality

0606/23/O/N/25 — Question 3 · 9 marks

(a)(i)
Write x26x2x^{2} - 6x - 2 in the form (x+a)2+b(x + a)^{2} + b, where aa and bb are constants.
[2]
(a)(ii)
Hence write down the coordinates of the stationary point on y=x26x2y = x^{2} - 6x - 2.
[2]
(b)
On the axes, draw the graph of y=x26x2y = x^{2} - 6x - 2 for 4x4-4 \leqslant x \leqslant 4.
[3]
(c)
Use your graph to solve the inequality x26x24x^{2} - 6x - 2 \leqslant 4.
[2]