Lettervormen getalwaarde

Bereken de getalwaarde

\(4ab-2b+12\text{ [met a = -1 en b = 4]}\)

\(\begin{align} 4ab-2b+12&=4.a.b-2.b+12 \text{ [met a = -1 en b = 4]}\\&=4.(-1).4-2.4+12\\&=-12\\ \end{align}\)