Răspuns:
[tex]a)3( {2 + 5x)}^{2} - x(2 + 5x) + 5(2 + 5x) = (2 + 5x)(3(2 + 5x) - x + 5)[/tex]
[tex]b)(x - y)(2x - y) + {(x - y)}^{2} - 3y(x - y) = \\ = (x - y)((2x - y )+ (x - y) - 3y)[/tex]
