Diketahui f(x)=x²+3x-1 dan g(x)=x+1 maka nilai dari (fog)(-1) adalah

(fog)(x)
= f(g(x))
= f (x+1)
= (x+1)^2 +3(x+1) -1
= x^2 +2x +1 + 3x + 3 -1
= x^2 + 5x +3

fog(-1) = (-1)^2 +5(-1)+3 = 1 -5+3 = -1

f(x) = x^2 + 3x -1
g(x) = x + 1
ditanya : (fog)(-1)
jawab :
f(g(x)) = f(x+1)
f(g(x)) = (x+1)^2 + 3(x+1) -1
f(g(-1)) = (-1 +1)^2 + 3(-1 +1) -1
f(g(-1)) = 0^2 + 3(0) -1 = -1

semoga bermamfaat ;;)