Question

Bantuin nomor 19 ya jelasinnnnn

Answer 1

(19)
bilangan x dan y
3x + y = 8
y = 8 - 3x

f= x² -y²
f = (x+y)(x-y)
f(x)= (x +8-3x)(x-8+3x)
f(x)= (8-2x)(4x-8)
f(x)= 32x - 64 -8x² + 16x
f(x)= -8x²+48x-64
nilai maksimum f(x) , jika  f ' x = 0
-16x + 48 = 0
x = 3
f(x)= (8-2x)(4x -8)
f(3)= (8-6)(12-8) =(2)(4)= 8
nila maksimum = 8