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Solve X2 + 7x = 7 and Give Your Answer Correct to Two Decimal Places - ICSE Class 10 - Mathematics

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Question

Solve x2 + 7x = 7 and give your answer correct to two decimal places

Solution

Given quadratic equation is x2 + 7x = 7

`=> x^2 + 7x - 7 = 0`

Comparing with `ax^2 + bx +c =0` we have a = 1, b = 7 and c = -7

`x = (-b+-sqrt(b^2 -4ac))/(2a) `

`=> x = (-7 +- sqrt(7^2 - 4 xx 1 xx (-7)))/(2 xx1)`

`=> x = (-7+- sqrt77)/2`

`=> x  = (-7+- 8.77)/2`

`=> x = (-7+8.77)/2` and `x = (-7-8.77)/2`

`=> x = 1.77/2` and `x = (-15.77)/2`

`=> x = 0.885 and x = -7.885`

=> x = 0.89 and x = -7.89 (correct to two decimal places)

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APPEARS IN

 2017-2018 (March) (with solutions)
Question 4.3 | 4.00 marks
Solution Solve X2 + 7x = 7 and Give Your Answer Correct to Two Decimal Places Concept: Quadratic Equations.
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