Odpowiedź:
zad.2
a)
[tex] \frac{x + 3}{x} = \frac{ - 3 + 3}{ - 3} = \frac{0}{ - 3} = 0[/tex]
b)
[tex] - 5 {x}^{2} - x = - 5 \cdot ( - 3 {)}^{2} - ( - 3) = - 5 \cdot \: 9 + 3 = - 45 + 3 = - 42[/tex]
c)
[tex] - 2x + 5 = - 2 \cdot \: ( - 3) + 5 = 6 + 5 = 11[/tex]
d)
[tex] \frac{x + 1}{x - 1} = \frac{ - 3 + 1}{ - 3 - 1} = \frac{ - 2}{ - 4} = \frac{1}{2} [/tex]
zad.3
[tex]p = (ab + ac + bc) \times 2[/tex]
[tex]p = (1 \times 2.1 + 1 \times 3.5 + 2.1 \times 3.5) \times 2 = (2.1 + 3.5 + 7.35) \times 2 = 12.95 \times 2 = 25.9[/tex]
zad.4
a)
[tex](x + y)(x - y) = ( - 3 + 2)( - 3 - 2) = - 1 \times ( - 5) = 5[/tex]
b)
[tex] \frac{3xy + 2}{2} = \frac{3 \times ( - 3) \times 2 + 2}{2} = \frac{ - 16}{2} = - 8[/tex]
c)
[tex]x(2x + {y}^{2} ) = - 3(2 \times ( - 3) + {2}^{2} ) = - 3( - 6 + 4) = 6[/tex]
