Respostas
1)
x² - 5x= 0
a = 1 b = -5 c=0
Δ= b² -4ac x = -b ±√Δ / 2a x'' = 5 - 5 / 2
Δ= - 5² - 4 . 1 .0 x =-( -5) ±√ 25/ 2 . 1 x''= 0 / 2
Δ= 25 - 0 x ' = 5 + 5/ 2 x'' = 0
Δ = 25 x' = 10/ 2 = 5 S = ( 5 ,0 )
2)
2x² - 18 = 0
a = 2 b= 0 c= -18
Δ= b² - 4ac x = -b± √Δ / 2a x'' = -2 -12 / 36
Δ= 0² - 4. 2. -18 x = - ( +2) ± √ 144/ 2. -18 x'' = -14 / 36 = -0,38
Δ= 0 + 144 x' = -2 + 12/ 36
Δ=144 x' = 10 / 36 = 0,27
3)
x² -4x + 8= 0
a = 1 b = -4 c= 8
Δ= b² - 4.a.c
Δ= -4² - 4. 1 . 8
Δ= 16 - 32
Δ= 16 Letra: d
4)
letra: A
5)
x² -3x +2 =0
a = 1 b = -3 c = 2
letra: A