Factor x^2 - x - 40

Question

I need help with this please

Answer 1

not factorable

 

 

 

Answer 2

This expression does not factor.

 

The factors of 40 are 1 and 40, 2 and 20, 4 and 10, and 5 and 8.

 

Since the last term is -40, one of the factors must be positive and one must be negative.

 

 

|40-1| = 39

|20-2| = 18

|10-4| = 6

|5-8| = 3

 

Since none of those = -1, the express is "prime" and can't be factored.

 

Answer 3

Hi,

To factor x^2 - x - 40, you have to put it into a quadratic formula and solve it that way.

1.  x^2 - x - 40 = 0 :  quadratic formula = x =[ -b + - (square root of b^2 - 4ac)] all divided by 2a.

2.  In this case: a = 1; b = -1; c = -40

     so: x = [-(-1) + - (square root of (-1)^2 - 4(1)(-40)] divided by 2(1).

3.  x=[1 + - (square root of (1 + 160)] divided by 2

4. x = [1 + - (square root of 161)] divided by 2