1)f'(x)=(8/x⁴)'-(4√x)'+(5x)'-(9)'=(8x⁻⁴)'- 4/2√x + 5=8×(-4)×x⁻⁵ - 2/√x + 5

=-32x⁻⁵ - 2/√x + 5

2)f'(x)=((x²-1)(x+3))'=(x²-1)'(x+3)+(x²-1)(x+3)'=2x(x+3)+x²-1=

=2x²+6x+x²-1=3x²+6x-1         f'(2)=3×2²+6×2-1=23

3)f'(x)=(x³)'-(12x)'=3x²-12

f'(x₀)=0  ⇒ 3x²-12=0

3x²=12

x²=4

x=±√4=±2

4)f'(x)=(4x³)'-(7x²)'+(x)'+(2)'=3×4x²-2×7x+1=12x²-14x+1