Question

dada a função f(x)= x2-3x-4

a) determine as suas raízes;

b) determine o vértice da parábola;​

Answer 1

∆=b² -4ac=(-3)² -4.1.(-4)= 9+16=25 => √∆=5

x = -b±√∆/2a

x = 3±5/2.1

x'= 3+5/2 = 8/2 = 4 ✓

x"= 3-5/2 = -2/2 = -1 ✓ => S:{ -1,4}

xv= -b/2a = 3/2 ✓

yv= -∆/4a = -25/4 ✓. => V:{3/2 , -25/4}