Question

Diketahui f(x)=ax + b, jika f(-3)=-11 dan f(1/3)=-1
Tentukan nilai a dan b

Answer 1

F(-3)=-11
masukan ke f(x)=ax+b
f(-3)=a(-3)+b
-11=-3a+b

masukkan f(1/3)=-1 ke persamaan f(x)=ax+b
f(1/3)=a(1/3)+b
-1=1/3a+b
----------------- dikali 3 biar mudah
-3=a+3b
 eliminasi keduanya
-11=-3a+b (x3) -33=-9a+3b
-3=a+3b    (x1) -3=a+3b
______________________ -
                      -30=-10a
                        a= 3
 substitusi ke -11=-3a+b
-11=-3(3)+b
 -11=-9+b
b=-2                 

Answer 2

F(x)= ax + b

f(-3)= -3a + b = -11
f()= a + b = -1
------------------------------------------------------------- / x3
-3a + b = -11
a + b = -1 ----------------> b= -1 -3 = -4
-------------------- -
-4a = -12
a = 3