The Difference of Square: a^2 - b^2 = (a + b)(a - b)

Sara did a question as: 2x^2 - 2y^2 = (2x + 2y)(2x - 2y).

What's wrong with Sara's work? How to fix it?

Find the gradient of f(x, y,z)equals=left parenthesis x squared plus y squared plus z squared right parenthesis superscript negative 1 divided by 2 baseline plus ln left parenthesis x right parenthesis x2+y2+z2−1/2+ln(xyz) at the point left parenthesis negative 2 comma 1 comma negative 2 right parenthesis(−2,1,−2).

Line wx is parallel to line yz. if m

1.based of the diagrams what is the the value of x? 2.how would you verify your answer for x