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Question
Solve for x using the quadratic formula. Write your answer correct to two significant figures.
(x – 1)2 – 3x + 4 = 0
Solution
`(x - 1)^2 - 3x + 4 = 0`
`=> x^2 - 2x + 1 - 3x + 4 = 0`
`=> x^2 - 5x + 5 = 0`
Here a = 1,b = −5 and c = 5
`:. x = (-b +- sqrt(b^2 - 4ac))/(2a)`
`= (-(-5) +- sqrt(-5)^2 - 4 xx 1 xx 5)/(2 xx 1)`
`= (5 +- sqrt(25 - 20))/2`
`:.x = (5 + 2.24)/2 or x = (5 - 2.24)/2`
`=> x = (7.24)/2 or x= (2.76)/2`
⇒ x = 3.6 or x = 1.4
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