If c is a constant such that 9x^2 + 8x + c is equal to the square of a binomial, then what is c?
9x^2 +8x+c divide thru by 9 ( x^2 coeff needs to be '1' to 'complete the square')
x^2 + 8/9x now take 1/2 of 8/9 (which is 8/18)
x^2 + 16/18 + 64/324 multiply by 9
9x2 + 8x + 16/9