Jawaban:

Penyelesaian :

di ketahui f(x) = ax + b jika f(2) = 4 dan f(5) = 13, maka nilai f(8) - f(3) ...

• f(x) = ax + b
• f(2) = 4
• f(5) = 13

Mencari Nilai f(8) - f(3)

• Buat persamaan dari rumus f(x)

f(x) = ax + b

f(2) = a(2) + b = 4

2a + b = 4 ... (i)

f(5) = a(5) + b = 13

5a + b = 13 ... (ii)

• Eliminasi b dari persamaan

2a + b = 4

5a + b = 13 (-)

-3a = -9

a = -9/-3

a = 3

• Substitusi a ke pers (i)

2a + b = 4

2(3) + b = 4

6 + b = 4

b = 4 - 6

b = -2

Maka nilai f(8) - f(3)

f(8) - f(3)

= (f(x) = ax + b) + (f(x) = ax + b)

= (3(8) + (-2) + (3(3) + -2)

= (24 - 2) + (9 - 2)

= (22) - (7)

= 22 - 7

= 15

'비상'