1)

[tex] \frac{1}{2} x + 4 = 0 \\ \frac{1}{2} x = - 4 \\ x = - 4 \div \frac{1}{2} \\ x = - 8[/tex]

2)

[tex]y = - {x}^{2} - 2x + 2a \\ y' = - 2x - 2 [/tex]