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CBSE Class 11-science Answered

 If the A.M. of the roots of a quadratic equation is 8 5 and A.M. of their reciprocals is 8 7 , then the quadratic equation is - (A) 5x2  – 8x + 7 = 0 (B) 5x2  – 16x + 7 = 0 (C) 7x2  – 16x + 5 = 0 (D) 7x2  + 16x + 5 = 0
Asked by modhavevedant | 10 Sep, 2020, 09:46: PM
answered-by-expert Expert Answer
begin mathsize 16px style Let space the space two space roots space of space the space required space Quadratic space Equation space be space straight alpha space and space straight beta. According space to space the space condition comma space we space get fraction numerator straight alpha space plus space straight beta over denominator 2 end fraction space equals space 8 over 5 rightwards double arrow straight alpha space plus space straight beta equals space 16 over 5 fraction numerator begin display style fraction numerator 1 over denominator straight alpha space end fraction plus 1 over straight beta end style over denominator 2 end fraction equals 8 over 7 rightwards double arrow fraction numerator straight alpha plus straight beta over denominator 2 αβ end fraction equals space 8 over 7 rightwards double arrow αβ space equals space fraction numerator 16 over 5 over denominator 2 cross times 8 over 7 end fraction equals 7 over 5 Therefore comma space the space required space Quadratic space Equation space is space straight x squared minus left parenthesis straight alpha plus straight beta right parenthesis straight x space space plus space αβ space equals space 0 rightwards double arrow straight x squared minus 16 over 5 straight x space space plus space 7 over 5 equals space 0 rightwards double arrow 5 straight x squared minus space 16 straight x space plus space 7 space equals end style
Answered by Yasmeen Khan | 11 Sep, 2020, 12:58: PM

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CBSE 11-science - Maths
For a real number r, the quadratics x² + (r - 1) x + 6 and x² + (2r + 1) x + 22 have a common real root. The sum of the possible values of r can be expressed as a/ b where a, b are relatively prime positive integers. Compute 10a + b
Asked by Bhaveshkr211 | 30 Jul, 2023, 05:21: PM
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CBSE 11-science - Maths
Pls solve
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Asked by sdmbotch1123 | 18 Jan, 2023, 11:01: PM
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CBSE 11-science - Maths
complete solution set of the equation |x^2-3|+|2-x|=|x^2-x-1|
Asked by rajshekhara348 | 20 Jun, 2022, 11:23: PM
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CBSE 11-science - Maths
let the equations be x^2+x+2=0 and ax^2+bx+1=0 have atleast one common root then a+b equals to
Asked by sandeepkumarbhadauria41 | 15 Sep, 2021, 02:52: PM
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CBSE 11-science - Maths
Please solve all of these questions with proper explanation
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Asked by Suchismitasingha18 | 07 Aug, 2021, 04:44: PM
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CBSE 11-science - Maths
questions 6
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Asked by sohailsidmd002 | 11 Oct, 2020, 02:35: PM
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CBSE 11-science - Maths
find the value of p and q if the equation px²+5x+2=0 and 3x²+10x+q=0 have both roots in common.
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Asked by ssroul.tcbls | 02 Jul, 2020, 07:15: PM
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CBSE 11-science - Maths
   the equation x minus 2 to the power 2 + x - 2 - 2 = 0 has how many roots
Asked by avinashjha3012 | 22 Jun, 2020, 05:41: PM
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CBSE 11-science - Maths
The quadratic equation, who's roots are reciprocal of the roots of the equation- ax^2+bx+c,is?
Asked by drhimasingh | 26 May, 2020, 11:31: PM
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CBSE 11-science - Maths
write the quadratic equation, the arithmetic mean, Geometric mean of whose roots are A and G respectively
Asked by amanamit818 | 06 Oct, 2019, 11:03: AM
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