Question

If x+a is a factor of 2x2+2ax+5x+10 find a zero of the polynomial

Answer 1

Let f(x)=2x^2+2ax+5x+10. If x+a is a factor f (-a)=0 f (- a)=2*((-a)^2)+2*a*(- a)+5*(-a)+10=0 2(a)^2-2(a)^2-5a+10=0

Answer 2

Answer:

-5/2

Step-by-step explanation:

• x+a=0

∴     x = -a

p(a)= 2(-a)²+2a×(-a)+5×(-a)+10=0

     =2a²-2a²-5a+10=0

     =-5a+10=0

   ∴a=2

p[x]=2x²+4x+5x+10

    =2x²+9x+10

2x²+9x+10/x+2=2x+5

2x+5=0

x=-5/2