Question

Equação do 2 grau
a) x²-2×=0
b) x²-16=0
c)-4x²+28×=0
d)x²-64=0
e) x²-10×+9=0
f) x²+8×+16=0
g) x²+4×-5=0
H)3 x²-7×+2=0
i)(×+2)²+×=0
j)3x²=2 (×-1)²+3=0

Answer 1

A)x²-2x=0
x(x-2)=0
x=0
x-2
x=2

B)x²-16=0
x²=16
x=√16
x=4

C)-4x²+28x=0
x(-4x+28)=0
x=0
-4x+28
-4x= -28
x= -28+4
x= -24

D)x²-64=0
x²=64
x=√64
x=8

E)x²-10x+9=0
a=1 b=(-10) c=9
∆=b²-4ac
∆=(-10)²-4.1.9
∆=100-36
∆=64√64=8
X= -b±√∆/2a
X= -(-10)±8/2.1
X=10±8/2
X'=10+8/2
X'=18/2=9
X"=10-8/2
X"=2/2=1

F)x²+8x+16
a=1 b=8 c=16
∆=b²-4ac
∆=8²-4.1.16
∆=64-64
∆=0√0=0
X= -b±√∆/2a
X= -8±0/2.1
X'X"= -8±0/2
X' X"= -8/2=-4

G)x²+4x-5=0
a=1 b=4 c=(-5)
∆=b²-4ac
∆=4²-4.1.(-5)
∆=16+20
∆=36√36=6
X= -b±√∆/2a
X= -4±6/2.1
X= -4±6/2
X'= -4+6/2
X'= 2/2=1
X"= -4-6/2
X"= -10/2
X"= -5

H)3x²-7x+2
a=3 b=(-7) c=2
∆=b²-4ac
∆=(-7)²-4.3.2
∆=49-24
∆=25√25=5
X= -b±√∆/2a
X= -(-7)±5/2.3
X=7±5/6
X'=7+5/6
X'=12/6=2
X"=7-5/6
X"=2/6=2:2=1 6:2=3

I)(x+2)²+x=0
x²+4+x=0
x²+x+4=0
a=1 b=1 c=4
∆=b²-4ac
∆=1²-4.1.4
∆=1-16
∆=-15√-15
∆=∅

J)3x²=2(x-1)²+3
3x²=2+x²-1+3
3x²-x²-2+1-3=0
2x²-4=0
2x²=4
x²=4-2
x²=2
x=√2
∅