Aufgabe 1

(x^2) - 3  x + 8 == Abs[2  x + 1]

Plot[{(x^2) - 3  x + 8, Abs[2  x + 1]}, {x, -10, 20}]

Plot[{(x^2) - 6  x + 8, Abs[2  x + 1]}, {x, -10, 20}, 
      PlotStyle -> {{Thickness[0.01], 
            RGBColor[1, 0, 0]}, {Thickness[0.01], 
            RGBColor[0, 1, 0]}}]

Solve[(x^2) - 3  x + 8 == Abs[2  x + 1], x]

Solve[(x^2) - 6  x + 8 == Abs[2  x + 1], x]

Aufgabe 2

links = 
      Plot3D[Abs[Abs[a] - Abs[b]], {a, -5, 5}, {b, -5, 5}]

rechts = Plot3D[Abs[a + b], {a, -5, 5}, {b, -5, 5}]

Show[links, rechts]

Aufgabe 3

(∑_(k = 1)^n) (k^2)

Aufgabe 4

(∑_(k = 0)^n) (q^k)