Which of the following shows that polynomials are closed under addition when two polynomials 4x2 − 8x − 7 and −5x + 16 are added?

4x2 − 13x + 9; may or may not be a polynomial
4x2 + 13x − 23; may or may not be a polynomial
4x2 − 13x + 9; will be a polynomial
4x2 + 13x − 23; will be a polynomial

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.

Given abcd ac=38 and ae=3x+4 find the value of x

Find the number of liters in 12.8 gal of gasoline. round to the nearest hundredths