a) – x2 - 4x +60 = 0
b) x2 - 6x - 7 = 0
c) x2 - 7x-18=0
d) 4x2 + 20x = 0
Soluções para a tarefa
Resposta:
a) x' = -7 x"= 10
b) x'= 7 x"= -1
c) x'= 9 x"= -2
d) x'=5 x"= 0
Explicação passo-a-passo:
a) -x²-4x+60 =0
a=-1
b=-4
c=60
-4² - 4× -1 × 60
16+240
∆=256
X'= -4+16 14
-------- = ----- = -7
-2 -2
X"= -4-16. -20
-------- = ------ = 10
-2 -2
b) x²-6x-7=0
a=1
b=-6
c=-7
-6² - 4 × 1 × -7
36+28
∆= 64
x'= 6+8 14
------ = ------ = 7
2 2
x" = 6-8 -2
------- = ------ = -1
2 2
c) x²-7x -18=0
a=1
b=-7
c=-18
-7² -4 × 1 × -18
49 + 72
∆ = 121
x'= 7+11 18
-------- = ------ = 9
2 2
x"= 7-11 -4
-------- = ------- = -2
2 2
d) 4x²-20x =0
a=4
b=-20
c=0
-20²-4 × 4 × 0
400+0
∆= 400
x'= 20+20 40
------------ = --------- = 5
8 8
x"= 20-20 0
---------- = ---------- = 0
8 8