Răspuns:
Explicație pas cu pas:
2.
5x + 5y = 5*(x + y)
(x - 16)^2 - 16 = (x - 16 + 4)(x - 16 - 4) = (x - 12)(x - 20)
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3.
cos B = AB/BC
BC = AB/cos B = 6 / (2/5) = 15 cm
BC^2 = AB^2 + AC^2
AC^2 = BC^2 - AB^2 = 225 - 36 = 189
AC = √189 cm = 3√21 cm
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4.
3(x + 3) = 2(x - 2) + 4
3x + 9 = 2x - 4 + 4
3x + 9 = 2x
3x - 2x = -9
x = -9
