What's wrong with this nested IF Statement

I am trying to create a nested IF statement to score a question. Here is the statement

if(#form/B1 = ‘3_4_personas’, 15, if(#form/B1 = ‘4_5_personas’, 14.25, if(#form/B1 = ‘5_7_personas’ = 10.5, if(#form/B1 = ‘m_s_de_8’, 6, 0)))).

But I get this error:

() function requires 3 arguments but 2 are present. in form “Encuesta de Inscripcion” Form in the “Surveys” Menu.

What is wrong with this IF statement?

Nevermind, figured it out. Here is the correct formula FYI:

if(#form/B1 = ‘3_4_personas’, 15, if(#form/B1 = ‘4_5_personas’, 14.25, if(#form/B1 = ‘5_7_personas’, 10.5, if(#form/B1 = ‘m_s_de_8’, 6, 0))))

There was an extra =