Răspuns:
Explicație pas cu pas:
36.
a + b = 10
(a + b)^2 = 10^2 = 100
a^2 + 2ab + b^2 - 25 = (a + b)^2 - 25 = 100 - 25 = 75
(a - b)^2 + 4ab + 3(a + b) = a^2 - 2ab + b^2 + 4ab + 3(a + b)
= (a^2 + 2ab + b^2) + 3(a + b) = (a + b)^2 + 3(a + b) = 100 + 3*10 = 130
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37.
x + y = 5
xy = 6
(x + y)^2 = 5^2 = 25
(x + y)^2 = x^2 + 2xy + y^2
x^2 + y^2 = (x + y)^2 - 2xy = 25 - 2*6 = 25 - 12 = 13
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41.
x + y = 3
ax + ay + bx + by = √27
a(x + y) + b(x + y) = √27
(x + y)(a + b) = √27
a + b = √27/(x + y) = √27/3 = 3√3/3 = √3
