kakak2 ini soal turunan tolong bantu dong...

34) misal x dan y
y + x² = 75
y = 75 - x²
x.y = x(75 - x²) = 75x - x³
nilai terbesar turunan = 0
75 - 3x² = 0
3x² = 75
x² = 25
x = 5
y + 25 = 75
y = 50
hasil kali x.y = 5×50 = 250

35) laba = 5.000x - (9000 + 1000x + 10x²)
= 5000x - 9000 - 1000x - 10x²
= -9000 + 4000x - 10x²
turunan = 0
4000 - 20x = 0
20x = 4000
x = 200

laba = 5000(200) - (9000 + 1000(200) + 10(200)²)
= 1.000.000 - (9000 + 200.000 + 400.000)
= 1.000.000 - (609.000)
= 391.000