3. f(x) = 4x2 + 6x + 7,x ∈ R
(a) Write f(x) in the form a (x+b)2
stating the values of a,b and C.
[5m]
f(x) = 4x²+6x+7
=H[ペナ岳x+(音部+
=4 [(x+2)2-36
=4++
19
64
:. A = 4, b = 1/4 C =
14
]
+7
(b) Write down the value of x for which f(x)
is a minimum and state the minimum value
off(x).
f(x)が最小となるxの値と
f(x) の最小値を述べなさい。
f(x)=19
x= -2/4, f(x) = 144
女
[2m]
(c) Find the set of values of x for which
f(x) <17.
f(x)<17
f(x)<17となる
[4m]
4x2+6x+1
Xの値のセットを求めなさい
4x2+6×-10-0
2 (2x²+3x-5) <0
(2x+5)(x-1)<0
+
囁くつく
x
5