Answer:
Explanation:
You asked: How do you know when to rewrite square trinomials and difference of squares binomials as separate factors? First, and mostly obviously is when the directions say to factor the given expression. Next, if you're given an equation and asked to solve it. You set it equal to 0 and factor the perfect square trinomial or the difference of squares binomial. Set each factor equal zero and solve. This is a little bit oversimplified but, solutions are roots are zeros are x-intercepts, so if you are asked to find any of those things. Set your equation equal to zero, factor and solve. Also, if you have a rational expression (a fraction with a polynomial on top and a polynomial on the bottom) you would need to factor in order to simplify, to sketch a graph without technology. Anytime you need to simplify, factoring is good to try.
You also asked: How can sums and differences of cubes be identified for factoring? The sum or difference of cubes is in the form a^3 + b^3 or a^3 - b^3
You can memorize how to factor these a^3 + b^3 = (a+b)(a^2 - ab + b^2) and
a^3 - b^3 = (a-b)(a^2 + ab + b^2)
If you take the trouble to multiply these two factors back together you will see how four terms drop out and you get a binomial. Also the is an acronym SOAP to help you memorize it. Factoring cubes is used in the same way as you previous question. To factor, to solve, to simply, to graph. This was a really general question. I hope this helps.