Question

Resolva as seguintes equações de 2 grau no conjunto dos números reais: 3ײ- 7×+4= 0 9ײ- 12× +4 =0 ײ+9×+8=0 3 ײ- 15 × + 12 =0 10 ײ + 72 × - 64 = 0

Answer 1

Explicação:

3x²-7x+4=0

A=3

B=-7

C=4

∆=b²-4ac

∆=(-7)²-4*3*4

∆=49-48

∆=1

-b±√∆/2a

7±√1/2*3

7±1/6

X¹=7+1/6=8/6(÷2)=>4/3

X²=7-1/6=6/6=>1

9x²-12x+4=0

(3x-2)²=0

3x-2=0

3x=0+2

3x=2

X=>2/3

X²+9x+8=0

A=1

B=9

C=8

∆=b²-4ac

∆=9²-4*1*8

∆=81-32

∆=49

-b±√∆/2a

-9±√49/2*1

-9±7/2

X¹=-9+7/2=-2/2=>-1

X²=-9-7/2=-16/2=>-8

3x²-15x+12=0(÷3)

X²-5x+4=0

A=1

B=-5

C=4

∆=b²-4ac

∆=(-5)²-4*1*4

∆=25-16

∆=9

-b±√∆/2a

5±√9/2*1

5±3/2

X¹=5+3/2=8/2=>4

X²=5-3/2=2/2=>1

10x²+72x-64=0(÷2)

5x²+36x-32=0

A=5

B=36

C=-32

∆=b²-4ac

∆=36²-4*5*-32

∆=1296+640

∆=1936

-b±√∆/2a

-36±√1936/2*5

-36±44/10

X¹=-36+44/10=8/10(÷2)=>4/3

X²=-36-44/10=-80/10=>-8