Lettervormen getalwaarde

Bereken de getalwaarde

\(ab+3b-7\text{ [met a = 5 en b = 5]}\)

\(\begin{align} ab+3b-7&=1.a.b+3.b-7 \text{ [met a = 5 en b = 5]}\\&=1.5.5+3.5-7\\&=33\\ \end{align}\)