diketahui fungsi g(x) = 2x -x2 jika g(a-2) = 4 + 8a - a2 maka nilai a adalah

Bab Fungsi 
Matematika SMA Kelas X

g(a - 2) = 4 + 8a - a²
g(a + 2 - 2) = 4 + 8 (a + 2) - (a + 2)²
g(a) = 4 + 8a + 16 - (a² + 4a + 4)
g(a) = 4 + 8a - a² - 4a - 4
g(a) = -a² + 4a

g(a) = g(a)
-a² + 4a = 2a - a²
-a² + a² + 4a - 2a = 0
2a = 0
a = 0/2
a = 0