Question

Sebuah fungsi f dirumuskan f ( x ) = ax + b jika f ( a ) = 19 ,f ( b ) = -9 dan ab = -12 nilai f ( a - b)

Answer 1

F(x) = ax + b | ab = -12
f(a) = a² + b = 19
f(b) = ab + b =-9
         -12 + b = -9
         b = 3
f(a) = a² + b = 19
a² + 3 = 19
a² = 16
a = 4 atau -4
f(a-b) = f(-4-3) = f(-7) = -7a + b = 31
f(a-b) = f(4-3) = f(1) = a + b = 7