340.8 will be the answer i know how to do surface area of a pyramid but this one is a little confusing i followed the formula and all that but i think this is the right answer, sorry if it was wrong 
        
             
        
        
        
The meter is the SI unit of measurement for length.
        
             
        
        
        
C would be the correct answer. You caanot multiply just one part of an equation, you must multiply the whole thing. All of the other steps follow this rule, so C is an incorrect step, and is therefore the correct choice.
Hope this helps!
 
        
                    
             
        
        
        
Answer:
Step-by-step explanation:
4x+y=14
x-2y=8
then;
x=8-2y
substitute;
4(8-2y)+8-2y=14
32-8y+8-2y=14
40-10y=14
26=10y
y=2.6 , work out 4x+2.6=14 to get x