Question

a) 3x² + 18x = 0
b) 4x² -84x = 0
c) 2x² -32=0
d ) x² - 12x +20 = 0​

Answer 1

Resposta:

Explicação passo a passo:

a.

3x²+18x=0

3x(x+6)=0

3x=0

x=0/3

x=0

x+6=0

x=0-6

x=-6

S={-6,0}

b.

4x²-84x=0

4x(x-21)=0

4x=0

x=0/4

x=0

x-21=0

x=0+21

x=21

S={0,21}

c.

2x²-32=0

2x²=0+32

2x²=32

x²=32/2

x²=16

x=√16

x=+4

x=-4

S={-4,+4}

d.

a=1

b=-12

c=20

x=12+-V(-12)²-4.1.20/2.1

x=12+-V144-80/2

x=12+-V64/2

x=12+-8/2

x'=12+8/2=20/2=10

x''=12-8/2=4/2=2

S={2,10}