Question

If 1 and -2 are two zeros of the polynomial (x³-4x²-7x+10), find it's third zero.​

Answer 1

p(x) = x³ - 4x² - 7x + 10

On comparing,

a = 1 , b = -4 , c = -7 , d = 10

We know,

➜ Sum of zeroes = - b / a

Let the third zero be Ɣ

So,

☛ 1 + (-2) + Ɣ = -(-4)/1

☛ 1 - 2 + Ɣ = 4

☛ Ɣ = 4 + 1

☛ Ɣ = 5

Hence, the third zero is 5

Answer 2

ATP
As -2 and 1 are it’s zeroes, it’s factors will (x+2) and (x-1)
Multiply x+2 and x-1 u will get x^2+x-2
Divide the above polynomial by x^2+x-2 u will get x-5
Therefore by equating it to zero u will x=5