text: I think your question is to factorise the given quadratic polynomial . to show square of a number  you should use  the symbol-cap: ^ (obtained by pressing together the keys:shift 6)\nso the polynomial is: (2y-7)^2 -1\n\nuse (a+b)^2 = a^2 + b^2 +2ab\n(2y -7)^2 = (2y)^2 + 7^2 -2(2y)(7)\npolynomial= 4y^2 -28y +49-1\n= 4y^2 -28y +48\n=4y^2 - 16y -12y +48\n= 4y(y-4) -12(y-4)\n=(4y-12)(y-4)