Question

Dada a função quadrática f(x)=(7x2 /4) - 2x +1 , determine:



a) f (-4)



b) f (8)

Answer 1

f(x) = 7x² / 4 - 2x + 1

f(-4) = ( 7 . (-4)² / 4 ) - 2 . 4 + 1

= (7 . 16 / 4 ) - 8 + 1

= ( 112 / 4 ) - 7

= 28 - 7

= 21

f(8) = ( 7 . (8)² / 4 ) - 2 . 8 + 1

= ( 7 . 64 ) / 4 ) - 16 + 1

= ( 448 / 4 ) - 15

= 112 - 15

= 97