Quadratics - the Australian Mathematical Sciences Institute
Quadratics - the Australian Mathematical Sciences Institute
Quadratics - the Australian Mathematical Sciences Institute
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A guide for teachers – Years 11 and 12 • {39}<br />
Answers to exercises<br />
Exercise 1<br />
a<br />
y<br />
b<br />
y<br />
–3<br />
x<br />
(–3, –4)<br />
–4<br />
3<br />
4<br />
1<br />
– 2<br />
0<br />
x<br />
Exercise 2<br />
The arms of <strong>the</strong> parabola y = x 2 are steeper.<br />
y<br />
y = x2<br />
y =<br />
1<br />
2 x2<br />
x<br />
Exercise 3<br />
y = 2(x − 1) 2 + 3<br />
Exercise 4<br />
The discriminant is 36k 2 − 16(4k + 1) and we set this equal to zero in order to obtain one<br />
real solution to <strong>the</strong> given equation. This gives 9k 2 −16k −4 = 0, which has solutions k = 2<br />
or k = − 2 9 .