Pecan trees yield 45 pounds per acre , And Jenna has p acres for pecan.
So total yield by pecan trees = (pounds per acre) times (total acres for pecan).
Hence, Total yield by pecan trees = 45 x p.
Now,
Hazelnut trees yield 25 pounds per acre and Jenna has h acres for Hazelnut.
So total yield by Hazelnut = (pounds per acre) times (total acres for hazelnut).
Hence, Total yield by Hazelnut = 25 x h.
Total yield = Pecan's yield + Hazelnut's yield.
Hence, so we got 45p + 25h = 900.