Question

Resolvas as seguintes equações do 2°grau.
a)x²+x(x-6)=0
b)x(x-3)=5x
c)x(x-3)-2(x-3)=6
d)(x+5)²=25
e)(x-2)²=4-9x
f)(x+1)(x-3)=-3

Answer 1

a)x²+x(x-6)=0

x²+x²-6x=0

2x²-6x=0

x(2x-6)=0

x=0

2x-6=0

2x=6

X=6/2

X=3

S={0,3}

b)x(x-3)=5x

x²-3x-5x=0

x²-8x=0

x(x-8)=0

x=0

x-8=0

x=8

S={0,8}

c)x(x-3)-2(x-3)=6
x²-3x-2x+6-6=0

x²-5x=0

x(x-5)=0

x=0

x-5=0

x=5

S={0,5}

 

d)(x+5)²=25
(x+5)(x+5)-25=0

x²+5x+5x+25-25=0

x²+10x=0

x(x+10)=0

x=0

x+10=0

x=-10[

S={-10,0}

 

e)(x-2)²=4x-9x
(x-2)(x-2)-4x+9x=0

x²-2x-2x+4-4x+9x=0

x²+x+4=0

 

 

S={ }

 

f)(x+1)(x-3)=-3

x²-3x+x-3+3=0

x²-2x=0

x(x-2)=0

x=0

x-2=0

x=2

S={0,2}