Alyssa gave the following explanation for factoring the trinomial x2 – 3x – 4: “I need to find factors of –4 that add to –3. 4 and –1 multiplies to –4 and adds to –3 so my factors are (x + 4)(x – 1).”

Part 1: Are Alyssa's factors correct? If not, explain where she made her mistake.

Part 2: What could Alyssa have done to check the accuracy of her factors before submitting her Module 3 test?

Question

Alyssa gave the following explanation for factoring the trinomial x2 – 3x – 4: “I need to find factors of –4 that add to –3. 4 and –1 multiplies to –4 and adds to –3 so my factors are (x + 4)(x – 1).”

Part 1: Are Alyssa's factors correct? If not, explain where she made her mistake.

Part 2: What could Alyssa have done to check the accuracy of her factors before submitting her Module 3 test?

anonymous · Answer

her facotrs are off

anonymous · Answer

yes 4 and -1 multiply to be -4 but they do not add to be -3

anonymous · Answer

-4 and 1

anonymous · Answer

(x-4)(x+1)

anonymous · Answer

her factors should have be -4 and 1. that way she would have had: (x-4)(x+1)=x^2-3x-4

anonymous · Answer

she could have checked her factors by foiling: (x+4)(x-1)

anonymous · Answer

she would have seen that she would get: x^2+3x-4, not x^2-3x-4

anonymous · Answer

she must multiply first to see if it is equal to the last number, then if it is, she must add both to verify that it equals the middle coeficient.

anonymous · Answer

^^^ that for Part 2: ?

anonymous · Answer

yes thats for the second part