In the previous clip we saw Ms. Coombs employ the “expand” feature on graphing calculator. In this clip, she challenges the students to use their earlier knowledge about distribution to go from the factored form to the expanded form.

Ms. Coombs continues to lead the discussion about a situation where Graphing Calculator has converted the function y = (x +4)(x + 6) to the expanded form y =x² + 10x + 24. She asks students to make observations about the connections between the two forms with a focus on multiplication. She leads the students to see a need to apply the distributive property, which they studied during the previous semester.

Ms. Coombs asks students to make a connection between the previously learned distributive property and the current topic of binomial multiplication. Students assign the placeholders a, b, and c from (a+b)c = ac + bc to the example y = (x + 4)(x + 6). She leads the class through the distributive process twice in order to write the binomial product in the expanded, quadratic form.

As part of the class work, Ms. Coombs has the students think once again about finding the zeros of a function in factored form.  This time, though, the factors are not restricted to having a leading coefficient of one. In this exchange, Ms. Coombs works with a student to find the zeros of y = (2x -1)(x – 4).