Question

Factor completely: x^2 − 4x − 21

(x + 7)(x − 3)

(x + 21)(x − 1)

(x − 7)(x + 3)

(x − 21)(x + 1)

Answer 1

What is the number when adding or subracting -4 and multiplying 21? @MixedBreedGirl

Answer 2

what do you mean?

Answer 3

We have to expand this equation so we have to find a number 2 intergals which when addingg or subracting are -4 so,
-7+3=-4 and when multiplying 21 so 7 x 3=21

Answer 4

So,
x^2 − 4x − 21
x^2-7x+3x-21
x(x-7)+3(x-7)
(x − 7)(x + 3)