Question

Fungsi f dinyatakn dengn rumus f(x) =ax+b . jika f(2) =3 dan f(-3) =13 ,nilai daRi -a=b adfalh
a . -12
b. -3
c , 9
d , 11

Answer 1

Pakai subtitusi eliminasi
F (2) = 2a+b =3
F (-3) = - 3a+b = 13
= - a = - 10
= a= 10
2a+ b =3
2(10) +b =3
B = 3-20
b = - 17

Answer 2

F(2) = a(2) + b
   3 = 2a + b

f(-3) = a(-3) + b
  13 = -3a + b

   3 = 2a + b
 13 = -3a + b 
-10 = 5a
  -2 = a

f(x) = ax + b
f(2) = (-2)(2) + b
   3 = -4 + b
   b = 4 + 3
   b = 7

-a + b = -(-2) + 7
          = 2 + 7
          = 9

Jadi jawabannya adalah yang c. 9.