Question

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19)Resolva as equações quadráticas:
A)x²-16=0
B)x²-10x=0
C)-7x+10+x²=0
D)-x²-x=-2
E)2x²+50=0
F)3x²=4x+15

Answer 1

a)
x²-16=0
x²=16
x=+-√16
x=+-4
x=-4 v x=4

b)
x²-10x=0
x(x-10)=0
x=0 v x-10=0
x=0 v x=-10

c)
-7x+10+x²=0
x²-7x+10=0
a=1, b=-7, c=10

∆=b²-4ac
∆=(-7)²-4*1*10
∆=49-10
∆=9

X=(-b+-√∆)/2
X=(7-+√9)/2
X=(7-9)/2 v X=(7+9)/2
X=-2/2 v X=16/2
X=-1 v X=8