Question

Se f(x) = 5x²-2, então o valor de f (-1) é:

 

a)4   b)-7    c)3     d) n.d.a

 

 

Observe a função 

f(x) =2x² + 5x-9

Calcule:

a- f(-1)___________________________________________

b- f(0)____________________________________________

c- f(1)____________________________________________

d-f(2)_____________________________________________

Answer 1

f(x) = 5x²-2
f(-1)=5.(-1)²-2
f(-1)=5-2
f(-1)=3
R: Alternativa C
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f(x) =2x² + 5x-9
a- f(-1)=2.(-1)²+5.(-1)-9
f(-1)=2+(-5)-9
f(-1)=-12

b-f(0)=2.0²+5.0-9
f(0)=0-9
f(0)=-9

c-f(1)=2.1²+5.1-9
f(1)=2-4
f(1)=-2

d-f(2)=2²+5.2-9
f(2)=4+1
f(2)=5