18:00
1 of 5
Higher
Non-calculator
A11 Roots and turning points
Question 1 · 4 marks
Spec and skills
Paper scope: Paper 1: non-calculator practice
Spec A11
Spec A18
Spec A6
Original practice question
Answer and supported method checks
E
=
x
2
−
8
x
+
20
E = x^2 - 8x + 20
E
=
x
2
−
8
x
+
20
(a)
By completing the square, show that
E
>
0
E > 0
E
>
0
for all values of
x
x
x
.
2 marks
x
2
−
8
x
+
20
=
x^2 - 8x + 20 =
x
2
−
8
x
+
20
=
x
xⁿ
a/b
√
π
(
)