Yes because 25x2-70x+49 = (5x-7)(5x-7) when factored
The given quadratic expression can not be factored as a perfect square.
Factors are (7y - 3)(7y - 2) so it's not a perfect square.
(x + 3)(x + 3)
Yes; the factored form would be (9c+4)(9c+4) or just (9c+4)2 Since the two factors are the same, the beginning trinomial 81c2+72c+16 is a perfect square trinomial
yes, (7x - 4)2
Yes because its discriminant is equal to zero