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Question
Solve the following quadratic equation using formula method only
`3"x"^2 +2 sqrt 5 "x" -5 = 0`
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Solution
`3"x"^2 +2 sqrt 5 "x" -5 = 0`
a = 3 ; b = `2 sqrt 5` ; c= -5
D = b2 - 4ac
= `(2 sqrt 5)^2` - 4 (3)(-5)
= 20 + 60
= 80
x = `(- "b" ± sqrt ("b"^2 - 4 "ac"))/(2a)`
x = `(-(2 sqrt 5) +- sqrt 80)/6`
x = `(-(2 sqrt 5) +- 4 sqrt 5)/6`
x = `(-(2 sqrt 5) +- 4 sqrt 5)/6`
x = `(-2 sqrt 5 + 4 sqrt 5)/6` , x = `(-2 sqrt 5 - 4 sqrt 5)/6`
x = `sqrt 5 / 3` , x = `- sqrt 5`
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