19 In Country the average hourly wage in dollars from 1960 f

#19

In Country the average hourly wage in dollars from 1960 f(x) = {0.078(x - 196) + 0.32 if 1960 lessthanorequalto x

Solution : f(x) = 9x²+ 5x , f(x+h) = 9( x+h)² +5(x+h)

: f(x+h) - f(x) = 9( x² +2xh +h²) +5x+5h - 9x² - 5x = 18xh + 9h²+5h = h( 18x + 9h+ 5)

: [ f( x+h) - f(x) ] / h = 18x + 9h + 5