Do you mean some thing like 4x2 - 28xy + 49y2 ? notice 4x2 = (2x)2 and 49y2 = either (7y)2 or (-7y)2 (1st and last terms must be squares) and the middle term is 2(2x)(-7y) (2 times sq root of 1st times sq root of last) Once the pattern is recognized: (sq root 1st + sqroot 2nd)2 or (sq root 1st - sqroot 2nd)2 depending on if middle term is positive or negative. So, back to my example: 4x2 - 28xy + 49y2 = (2x - 7y)2 because middle is negative. Simpler example factor x2 + 6x + 9. 1st and last are both squares sq root of 9 = 3 3 times 2 = 6 that fits the middle so x2 + 6x + 9 = (x + 3)2
4x2+20x+25 (2x+5)^2
x3 + 4x2 + x + 4 = (x + 4)(x2 + 1)
The quadratic 4x2+24x+11 = (2x+1)(2x+11)
4x2-36x+81 (2x-9)(2x-9)
4x2 - 23xy + 15y2 = (4x - 3y)(x - 5y)
4(x + 1)(x + 1)
4(x + 2)(x + 1)
4(x + 2)(x + 2)
4(x^2 + 2x + 8)
(2x - 5)(2x - 5)
(2x + 3)(2x - 1)