Question

If -1and2 are two zeroes of the polynomial 2x^3-x^2-5x-2 find the third zero

Answer 1

Answer:

-1/2

Step-by-step explanation:

by substituting any one value you can get a quadratic equation

the equation is 2x^2+3x+1

this is the equation you will get by substituting -1

now find factors

now use formula [-b plus or minus root of b^2-4ac]/2a

a=2

b=3

c=1

now substitute in formuula

[-3+ or - root of 9-4[2][1/2a

[-3 plus or minus9-8]/4

[-3 plus or minus 1]/4

[-3+1]/4=-2/4=-1/2

or

[-3-1]/4=-4/4=-1

therefore the zero are -1/2