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Jawab:

#dirumahsajalah

7.  y = x³  + 9x² + 27x – 10

y' = 0

3x² +18x + 27 = 0

x² + 6x +  9 = 0

(  x + 3)²    = 0

x = – 3

f(-3) = -37

titbel = (- 3, – 37)

8.  f(x) =  2x³ – 3x² – 72 x + 18

f'(x) > 0

6x² – 6x – 72 > 0

x² – x – 12 > 0

(x – 4)(x + 3 ) > 0

x < – 3  atau x >  4

3.  x +  y = 48

p = (xy)^2

p(x)= (x)(48-x)

P(x)=   48x – x^2

p'(x)= 0  

48 – 2x  =0

x=  24

x + y = 48

y = 24

selisih = 0