Question

Na função f(x) = -2x² – 5x + 6 = 0, calcule :
a) f(-2)
b) f(4)

Answer 1

Vamos lá!

a) f( - 2)

f( x) = - 2x² - 5x + 6

f( - 2) = - 2 . ( - 2)² - 5 . - 2 + 6

f( - 2) = - 2 . 4 + 10 + 6

f( - 2) = - 8 + 16

f( - 2) = 8

b) f( 4)

f( x) = - 2x² - 5x + 6

f( 4) = - 2 . 4² - 5 . 4 + 6

f( 4) = - 2 . 16 - 20 + 6

f( 4) = - 32 - 14

f( 4) = - 46