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What are the roots of 12x = 9 + 5x2?

1 Answer

4 votes
minus 12x both sides
0=5x^2-12x+9
use quadratic formula
for 0=ax^2+bx+c
x=
(-b+/- √(b^2-4ac) )/(2a)

given
5x^2-12x+9
a=5
b=-12
c=9
remember: i=√-1

x=
(-(-12)+/- √((-12)^2-4(5)(9)) )/(2(5))
x=
(12+/- √(144-180) )/(10)
x=
(12+/- √(-36) )/(10)
x=
(12+/- (√(-1))(√(36)) )/(10)
x=
(12+/- i(√(36)) )/(10)
x=
(12+/- 6i )/(10)
x=
(6+/- 3i )/(5)

the roots are
x=
(6+ 3i )/(5) and
(6- 3i )/(5)


User Hankduan
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