Question

Resolva as equações:

a) x²+2x-15 = 0

b) x²+4x-12 = 0

c) x²+12x+32 = 0

d) x²+6x-7 = 0

e) x²+3x+10 = 0

f) x²+2x-3 = 0

Answer 1

a) x²+2x-15=0
x²+5x-3x-15=0
x.(x+5)-3(x+5)=0
(x+5).(x-3)=0
x+5=0
x-3=0

x1= -5 x2= 3

b)x²+4x-12=0
x²+6x-2x-12=0
x.(x+6)-2(x+6)=0
(x+6).(x-2)=0
x+6=0
x-2=0
x1= -6 x2=2

c)x²+12x+32=0
x²+8x+4x+32=0
x.(x+8)+4+(x+8)=0
(x+8).(x+4)=0
x1= -8 x2=-4

d) x ²+6x-7=0
x ²+7x-x-7=0
x.(x+7)-(x+7)=0
(x+7).(x-1)=0
x1=-7 x2=1

e) x ²+3x+10=0
X^2 -3x -10 = 0

x^2 -5x + 2x - 10 = 0

(x - 5) (x + 2) = 0
(tem outro jeito de resolver)

>> x ²+3x+10=0
x= -3 +- √3 ²-4.1.10/2.1
x= -3 +- √9-40/2
x= -3 +- √-31/2

x E R (x pertence aos reais)

(Acredito que é essa fórmula que seu professor quer que você use)


f) x ²+2x-3=0
x ²+3x-x-3=0
x.(x+3)-(x+3)=0
(x+3).(x-1)=0
x+3=0
x-1=0
x1= -3 x2= 1