Question

necessito do desenvolvimento pfvr me ajudeem !!!

Answer 1

6) a) 7x^2+2=30
7x^2=30-2
7x^2=28
x^2=28/7
x^2=4
x= raiz de 4
x=-/+ 2
b) 2x^2-90=8
2x^2=8+90
2x^2=98
x^2=98/2
x^2=49
x= raiz de 49
x= -/+ 7
c) 4x^2-27=x^2
4x^2-x^2=27
3x^2=27
x^2=27/3
x^2=9
x= raiz de 9
x=-/+ 3
d) 8x^2=60-7x^2
8x^2+7x^2=60
15x^2=60
x^2=60/15
x^2=4
x= raiz de 4
x=-/+ 2
7) a) 3.(x^2-1)=24
3x^2-3=24
3x^2=24+3
3x^2=27
x^2=27/3
x^2=9
x= raiz de 9
x=-/+ 3
b) 2(x^2-1)=x^2+7
2x^2-2=x^2+7
2x^2-x^2=7+2
x^2=9
x= raiz de 9
x=-/+ 3
c) 5.(x^2-1)=4.(x^2+1)
5x^2-5=4x^2+4
5x^2-4x^2=4+5
x^2=9
x= raiz de 9
x= -/+ 3
d) (x-3).(x-4)+8=x
x^2-4x-3x+12+8=x
x^2-4x-3x-x+12+8
x^2-8x+20=0
delta=b^2-4ac
delta=(-8)^2-4.1.20
delta=64-80
delta=-16
delta negativo, não há raízes reais
8) a) x^2-7x=0
x(x-7)=0
x=0
x-7=0
x=0+7
x=7
b) x^2+5x=0
x(x+5)=0
x=0
x+5=0
x=0-5
x=-5