Question

Sarah factored x2−10x+21
and found the answer to be(x−7)(x−3)
. Is she correct?

Answer 1

No the correct answer is -8x+21 to find this you got to use the commutative property to recorder the terms x2-10x+21 so you will want to flip x and 2 so now it will be 2x-10x+21 and then collect like terms 2x-10x+21 so forget about the +21 and - the 2x-10x and you will get -8x and then and back the + 21 and you get -8x + 21 and that’s your answer

Answer 2

(x-3) (x-7)

Explanation:

Yes she is correct because

Break the expressions into groups

= (x^2-3x)+(-7x+21)

Factor out x from x^2 - 3: x (x - 3)

Factor out -7 from -7 + 21: -7 (x - 3)

= x(x-3)-7(x-3)

Factor out common terms x - 3

Answer: = (x-3)(x-7)