1 . diketahui f(x) = x²+2x-3, g(x) = x-5 tentukan nilai a jika ( f · g ) (a) = 5 tolong ane gan 2. diketahui (f-g) (x) = x³+3x³-8x tentukan f(x) jika 9 (x) = x

f (x) = x^2 + 2x - 3, dan g(x) = x -5
f o g (x) = f { g(x) }
= f (x - 5)
= (x -5)^2 +2(x - 5)- 3
= x^2 - 10x +25 +2x - 10 - 3
= x^2 - 8x + 12
f o g (a) = 5
a^2 - 8a + 12 = 5
a^2 - 8a + 7 = 0
(a - 1)( a - 7) = 0
a = 1 atau a = 7
2) (f - g) = x^3 + 3x^2 - 8x
(f - g)(x) = f(x) - g(x)
x^3 + 3x^2 - 8x = f (x) - (x + 1)
f (x) = x^3 + 3x^2 - 8x + (x +1)
f (x) = x^3 + 3x^2 - 7x + 1