If a is a constant such that 4x^2-12x+a is the square of a binomial, then what is a?
factor out a 4 then complete the square
4(x^2 - 3x)
-3/2
(-3/2)^2 = 9/4
4(x^2-3x+9/4)
4(x^2-3x+9/4) -9 cause 9/4 * 4 = 9, so you added 9 you need to subtract 9 to equalize
a = -9