Question

Calcule o valor da função y= -4x(ao quadrado) - 2x
A) x= - 4
B)x=-2,5
C) x= 4
D) x= 15
E)x= -16

Answer 1

f(x)= -4x²-2x  p/ x-4

f(-4)=-4.(-4)²-2(-4)⇒ f(x)=-4.16+8=-64+8=-56       ( -4;-56)

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b)f(x)= -4x²-2x  p/ x=-2,5

f(-2,5)=-4(-2,5)²-2(-2,5)⇒ -4.(6,25)+5=-2,5 +5=2,5....  ( -2,5 ; 2,5)

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c)f(x)= -4x²-2x  p/ x=4

f(4)=-4(4)²-2.4 ⇒ -4.16-8 =-64-8=-72...... ( 4; -72)

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d)f(x)= -4x²-2x  p/ x=15

f(15)=-4. 15²-2.15=4.225-30=900-30=870....... ( 15 ; 870)

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e)f(x)= -4x²-2x  p/ x= -16

f(-16)= -4.(-16)²-2.(-16)

f(-16)= -4.256+32

f(-16)= -1024+31=-992....... ( -16; -992)