Odpowiedź:
a)
f(x) = ax + b
f(0) = a * 0 + b = b = - 4
f(2) = a * 2 + b = 2a + b = 2
b = - 4
2a + b = 2
2a - 4 = 2
2a = 2 + 4 = 6
a = 6/2 = 3
f(x) = ax + b = 3x - 4
b)
f(3) = 3a + b = 1
f(4) = 4a + b = - 1
Układ równań
3a + b = 1
4a + b = - 1
odejmujemy równania
3a - 4a + b - b = 1 + 1
- a = 2
a = - 2
3a + b = 1
3 * (- 2) + b = 1
- 6 + b = 1
b = 1 + 6 = 7
f(x) = ax + b = - 2x + 7
