How can the common difference between 375-315=30

You are making a battery for a science project. you have copper wire for your first electrode. you need to choose a conductor, a second electrode, and a device to plug into your battery. you have already chosen a lemon conductor. complete each statement below about the options that include a lemon conductor.

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)

What is 140% of 25? because i need