How do you write y=x^3+6x^2-25x-150y=x3+6x2−25x−150 in factored form?
1 Answer
Apr 21, 2018
Explanation:
The difference of squares identity can be written:
A^2-B^2 = (A-B)(A+B)A2−B2=(A−B)(A+B)
We will use this with
Given:
y = x^3+6x^2-25x-150y=x3+6x2−25x−150
Note that the ratio between the first and second terms is the same as that between the third and fourth terms.
So this cubic will factor by grouping:
y = x^3+6x^2-25x-150y=x3+6x2−25x−150
color(white)(y) = (x^3+6x^2)-(25x+150)y=(x3+6x2)−(25x+150)
color(white)(y) = x^2(x+6)-25(x+6)y=x2(x+6)−25(x+6)
color(white)(y) = (x^2-25)(x+6)y=(x2−25)(x+6)
color(white)(y) = (x^2-5^2)(x+6)y=(x2−52)(x+6)
color(white)(y) = (x-5)(x+5)(x+6)y=(x−5)(x+5)(x+6)