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Question
Make c the subject of formula x = `(-"b" ± sqrt("b"^2 - 4"ac"))/(2"a")`
Solution
x = `(-"b" ± sqrt("b"^2 - 4"ac"))/(2"a")`
⇒ 2ax = `-"b" ± sqrt("b"^2 - 4"ac")`
⇒ 2ax + b = `± sqrt("b"^2 - 4"ac")`
Taking square both sides
⇒ (2ax + b)2 = b2 - 4ac
⇒ 4ac = b2 - (2ax + b)2
⇒ c = `("b"^2 - (2"ax" + "b")^2)/(4"a")`.
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