Anonymous

You need 3 equations, x, y and z. If there is no equation that says the value of z then you will not get answer.

Anonymous

x + y = 7 and xy = 10 y = (7 - x) x (7 - x) = 10 x^2 - 7x + 10 = 0 (x - 2)(x - 5) = 0 x = 2, y = 5 x = 5, y = 2 1/x^2 + 1/y^2 = (x^2 + y^2)/x^2y^2 = 29/100

Anonymous

x + y = 7 x y = 10 1/x^2 + 1/y^2 = (x^2 + y^2)/(x^2 y^2) = [(x + y)^2 - 2xy] / (xy)^2 = (49 - 20) / 100 = 29/100

Anonymous

　 x + y = 7 xy = 10 x² + y² = (x+y)² − 2xy = 7² − 2(10) = 29 1/x² + 1/y² = (x²+y²)/(xy)² = 29/10² = 29/100 = 0.29

Anonymous

If x+y=7 and xy=10 find value of 1/x² + 1/y² 1/x² + 1/y² = (x² + y²)/(xy)² = (x² + 2xy + y² - 2xy)/(xy)² = ((x + y)² - 2xy)/(xy)² = (7² - 2×10)/10² = 29/100

Anonymous

0.29

Anonymous

x + y = 7 x * y = 10 x = 7 - y (7 - y) * y = 10 7y - y^2 = 10 y^2 - 7y = -10 y^2 - 7y + 10 = 0 (y - 5) * (y - 2) = 0 y = 2 , 5 x = 5 , 2 1/x^2 + 1/y^2 => 1/25 + 1/4 => 4/100 + 25/100 => 29/100

Anonymous

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Anonymous

x+y *****