Question

VA ROGG !!!!!!!!!!!!!!​

Answer 1

Explicație pas cu pas:

a)

E(x) = 4x²-4x+1 - (x²+2x+1) + (x²-4) - 3x² + 15 = 4x²-4x+1-x²-2x-1+x²-4-3x²+15 = x² - 6x + 11

b)

$E(1 - \sqrt{3} ) = (1 - \sqrt{3} )^{2} - 6(1 - \sqrt{3}) + 11 = 1 - 2 \sqrt{3} + 3 - 6 + 6 \sqrt{3} + 11 = 9 + 4 \sqrt{3}$

c)

$E(x) = {x}^{2} - 6x + 11 = ({x}^{2} - 2 \cdot 3x + {3}^{2}) + 2 = {(x - 3)}^{2} + 2 \geqslant 0 + 2 = 2$

q.e.d.