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Question
Solve the following quadratic equation using formula method only
15x2 - 28 = x
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Solution
15x2 - 28 = x
15x2 - x - 28 = x
a = 15 ; b = -1 ; c = -28
D = b2 - 4ac
= (-1)2 - 4(15)(-28)
= 1 + 1680
= 1681
x = `(- "b" ± sqrt ("b"^2 - 4 "ac"))/(2a)`
x = `(1 +- sqrt 1681)/30`
x = `(1 + 41)/30` , x = `(1 - 41)/30`
x = `42/30` , x = `-40/30`
x = `7/5` , x = `-4/3`
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