Find and simplify the difference quotient

Question

Find and simplify the difference quotient: f(x+h) - f(x) / h, where h cannot = 0, for the function: f(x)= 3x² - x +2

 

Have tried this multiple times and still get the same answer which is not correct

 

Please help ASAP!

 

Thanks :)

Answer 1

f(x)= 3x² - x +2

f(x+h)= 3(x+h)² - (x+h) +2

f(x+h)=3(x²+2xh+h²)-x-h+2=3x²+6xh+3h²-x-h+2

f(x+h)-f(x)=3x²+6xh+3h²-x-h+2-3x²+x-2=6xh+3h²-h

(f(x+h)-f(x))/h=6x+3h-1=6x-1+3h