jawab : . . .
2. diket f(x) = x² + ax + b jika f(4) = f(-3) = 0 tentukan f(2)?
jawab : . . .
3. diket f(x) = x² + ax + b jika f(2) = -8 dan f(4) = 0 tentukan f(1)?
jawab : . . .
1. diket f(x) = x² + ax + 5 jika f(2) = 21 tentukan f(-3)?
Jawab:
nilai fungsi
1. diket f(x) = x² + ax + 5 jika f(2) = 21 tentukan f(-3)?
jawab :
f(2) = 21
2² + a(2) + 5= 21
4 + 2a + 5= 21
2a + 9 = 21
2a= 12
a= 6
f(x)= x² + 6x + 5
f(3) = 3²+6(3) + 5
f(3)= 9 + 18 + 5
f(3) = 32
2. diket f(x) = x² + ax + b jika f(4) = f(-3) = 0 tentukan f(2)?
jawab :
f(4) = 0
4²+a(4) + b = 0
16 + 4a + b = 0
4a+ b = – 16
f(-3) = 0
(-3)²+ a(-3) + b = 0
9 -3a + b = 0
-3a + b = – 9
eliminasi
4a+ b = -16
-3a + b = -9 –
7a = – 7
a= – 1
4a + b = -16
4(-1) + b = – 16
-4 + b = – 16
b = – 16 + 4
b = – 12
f(x) = x² – x - 12
f(2) = 2² – 2 -12
f(2) = 4 -2 – 12
f(2) = -10
3. diket f(x) = x² + ax + b jika f(2) = -8 dan f(4) = 0 tentukan f(1)?
jawab :
f(-2)= – 8
(-2)²+ a(-2) + b = -8
4 – 2a + b = -8
-2a + b = – 4
f(4)= 0
4²+ a(4) + b = 0
16+ 4a + b= 0
4a+ b = -16
eliminasi
-2a + b = -4
4a + b = – 16 (-)
-6a = 12
a= – 2
-2a + b = – 4
-2(-2) + b = – 4
4 + b = – 4
b = -4 – 4
b = – 8
f(x) = x² – 2x – 8
f(1) = 1² – 2(1)- 8
f(1)= 1 – 2 – 8
f(1) = – 9