Question

Which shows one way to determine the factors of x3 – 9x2 + 5x – 45 by grouping?

x2(x – 9) – 5(x – 9)

x2(x + 9) – 5(x + 9)

x(x2 + 5) – 9(x2 + 5)

x(x2 – 5) – 9(x2 – 5)y

Answer 1

x2(x-9)-5(x-9)

Explanation:

simplifying the factors

(x²-5)*(x-9)

x²*x=x³,x²-9=9x²,-5*x=-5x,-5*9=45

using the identity rule

x³-9x²+5x-45

Answer 2

x^2(x – 9) + 5(x – 9)

Explanation:

x^3 – 9x^2 + 5x – 45

To factor by grouping, we can take out an x^2 out of the first group of 2 terms

x^2 ( x-9) + 5x -45

We can take out a -5 out of the last 2 terms

x^2 ( x-9) + 5( x-9)