BD Merit - Freelancing, BCS, Bank, Primary, Admission, NTRCA

1 . x-y=10,xy=5

A. 80
B. 120
C. 110
D. 90

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Answer: Option B

Explanation:

দেওয়া আছে, x - y = 10 এবং xy = 5 x^{2} + y^{2} = {(x - y)}^{2} + 4 xy = {(10)}^{2} + 4.5 = 100 + 20 = 120

2 . x-y=10

A. 20
B. 30
C. 40
D. 50

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Answer: Option B

Explanation:

x - y = 10 x^{3} - y^{3} = 1900 x y = ? x^{3} - y^{3} = {(x - y)}^{3} + 3 x y (x - y) 1900 = {(10)}^{3} + 3 x y . 10 1000 + 30 x y = 1900 30 x y = 1900 - 1000 30 x y = 900 x y = \frac{900}{30} x y = 30

3 . x-y=10,xy=5

A. 80
B. 120
C. 110
D. 90

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Answer: Option B

Explanation:

দেওয়া আছে , x-y =10 এবং xy =5 x^{2} + y^{2} = {(x - y)}^{2} + 4 xy = 10^{2} + 4.5 = 100 + 20 = 120