Step-by-step explanation:
=>x⁴-5x²+4
=>x⁴-x²-4x²+4
=>x²(x²-1)-4(x²-1)
=>(x²-1)(x²-4)
=>(x+1)(x-1)(x+2)(x-2)
hope this helps you.
Answer:

Explanation:

Factor out 3

Cancel out the common factor 3

Answer:
If you have a perpendicular shape, like a plus sign, usually what I was taught, right whole side of the "plus" sign are negative. The left side is positive. I think it's how you say it.
Answer:
-3 and 5
Step-by-step explanation:
f(n) = n² - 2n - 15
numbers whose product is -15 and sums up to -2 = -5 and 3
= n²- 5n+3n - 15
= n(n - 5) +3 (n - 5)
f(n) = (n + 3)( n - 5)
n + 3 = 0 n - 5 = 0
n = -3 n = 5
Roots = -3 and 5