Question

Como fazer a formula do delta em : s= -15+8t-t²

Answer 1

-t² +8t -15=0 ===> *(-1)

t² -8t +15=0 ,=> a=1, b=-8, c=15

∆= (-8)² -4.1.15 = 64 -60=4 => √∆=2

t= -b±√∆/2a

t= 8±2/2

t'= 8+2/2 = 10/2 = 5s ✓

t" = 8-2/2 = 6/2 = 3s ✓