Solve the Equation: (x+3)(x-3) = x²+x Step by Step

Let's solve the equation. First, we'll simplify the algebraic expressions using the difference of squares formula:

$(a+b)(a-b)=a^2-b^2$We'll apply this formula and expand the parentheses in the expressions in the equation:

$(x+3)(x-3)=x^2+x \\ x^2-3^2=x^2+x \\ x^2-9=x^2+x$We'll continue and combine like terms. After moving terms around, we can see that the squared term cancels out, therefore it's a first-degree equation, which we'll solve by isolating the variable term on one side and dividing both sides of the equation by its coefficient:

$x^2-9=x^2+x \\ -9=x\\ \downarrow\\ \boxed{x=-9}$Therefore, the correct answer is answer B.