[tex]f(x) = 7x {}^{2} - 20x + 13 \\ x_0 = 2 \\ f'(x_0) - ? \\ f'(x)= 14x - 20 \\ f'(x_0) = f'(2) = 14 \times 2 - 20 = - 8 \\ f'(x_0) = - 8[/tex]