Question

Os valores que x pode assumir na função g (x)=-5x²+5x+60 para que g (x)≥0 ?

Answer 1

-5x² + 5x + 60 .(-1)
5x² - 5x -60 ≥ 0 :5
x² -x - 12 ≥ 0 
Δ = b² -4ac
Δ = (-1) ²- 4 . 1 . (-12)
Δ = 1+ 48
Δ= 49
√Δ = 7

x = -b+/-√Δ / 2a
x = -(-1) +/- 7 / 2.1
x = 1 +/- 7 / 2
x' = 1+ 7 / 2 ~~> 8/2 ~~> 4
x" = 1 - 7 / 2 ~~> 6 / 2 ~~> 3
     
x' = 4 e x" = 3