Question 165310
You can apply the "Remainder/Factor theorem" which basically states that:
"If the function P(x) is divided by (x+a) and the remainder is zero, then (x+a) is a factor of P(x).
When you do this division, ({{{(x^4-7x^2+4x+20)/(x+2)}}}) you will find that you get {{{x^3-2x^2-3x+10}}} with a zero remainder. So (x+2) must be a factor of the given function (P(x)).