2. Prove that a sequence {n} converges to z if and only if the real sequence | - z converges to 0.

Can you help me with question 1 please?

2. From the list of equations below, CIRCLE ALL quadratics with complex roots. (a) y=2x²-7x+6 (b) y=3x²+2x+1 (d) y=2x²-12x+26 Explain your reasoning: (e) y=-2x² +6x-5 (c) y=x²-8x+14 (f) y=4x² - 4x+1

23. Explain why the equation x³ + x +1 = 0 has no real roots and why each of its complex roots is constructible.

please help me with my homework question 3 and 4