nomer 3-5 ..........

3) titik x maksimum turunan = 0
10x⁴ - 20x³ = 0
10x³(x - 2) = 0
x = 2 atau x = 0

4) L = (2x + 4)(4 - x)
L = 8x - 2x² + 16 - 4x = -2x² + 4x + 16
maksimum turunan = 0
-4x + 4 = 0
-4x = -4
x = 1
p = 2x + 4 = 2(1) + 4 = 6