Question

11. Encontre as raízes da

f(x) = -x2 + 7x - 10.

a) 1 e 4
b) 3 e 5
c) 5 e 2
d) 9 e 1​

Answer 1

∆=b² -4ac = 7² -4.(-1).(-10) = 9 => √∆=3

x' = -b+√∆/2a = -7+3/-2= -4/-2 = 2 ✓

x'' = -b-√∆/2a = -7-3/-2= -10/-2 = 5 ✓ => c)