Combining sum and difference patterns, polynomial pattern matching

Questions
1

I’m writing an activity to help students with the distributive property using area models. I’m using pattern matching to give them feedback, and I’m stuck on how to check a specific polynomial.

The exercise is to multiply (x+5)(2x-3) , which equals 2x^2+7x-15

I am trying to give them a bit of flexibility in writing this, but I actually can’t figure out how to check that the terms are in this order and allow for both the + and the -

I CAN get Desmos to recognize 2x^2+(7x-15) using p.sum and p.difference, but it insists on the parentheses around 7x-15.

I CAN get it to recognize 2x^2+7x-15 by using p.sum().allowNegativeTerms , but then it’s fine with 2x^2-7x-15 , which is mathematically incorrect.

It’s screen 14 in this activity right now! (If I happen to move it around, it’s 3-67c):

Thanks all!

2

I generally use both pattern for checking the structure and then plugging in test values for checking the value. If it passes both tests then it is correct. I have coded up something like what you want, though I don’t restrict it to be in standard form.

See if this helps you: repeat and allowNegativeTerms patterns to check trinomial or factored form quadratic • Activity Builder by Desmos

3

Thanks @Daniel_Wekselgreene !

The combination strikes a good balance between flexibility and structure, and solves my problem!