the sum of the roots of a quadratic equation. is 7 and the sum of their cubes is 133. to find the quadratic equation, fill in the empty boxes.
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Answered by
4
Answer:
Given x +y= 7
X cube+ycube=133
We know (x+y)^3=x^3+y^3+3xy(x+y)
Substituting the given, equation becomes
7^3=133+3xy(7)
343=133+21xy
Hence xy=10
We know (x+y)^2=x^2+y^2+2xy
Substitute values of x+y and xy
7^2=x^2+y^2+20
49–20= x^2+y^2
Hence sum of their squares is 29
Step-by-step explanation:
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Answered by
8
Given :-
- x + y = 7
- x³ + y³ = 133
To Find :-
- The quadratic equation
Solution :-
x + y = 7
x³ + y³ = 133
Now,
(x+y)³ = x³ + y³ + 3xy(x+y)
=> 7³ = 133 + 3xy(7)
=> 343 = 133 + 3xy(7)
=> 343 - 133 = 21xy
=> 210 = 21xy
=> xy = 210/21
=> xy = 10
Now,
Sum of Zeroes = x + y = 7
Product of Zeroes = xy = 10
Putting the value in the equation below we get,
x² + (Sum of zeroes) x + (product of Zeroes)
=> x² + ( x + y ) x + (xy)
=> x² + (7)x + (10)
=> x² + 7x + 10
∴ x² + 7x + 10 is the required answer .
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