Question

what is the answer of thi question???

Answer 1

p(x) = x^2 + 2x - 15
       = x^2 + 5x - 3x -15
       = x(x+5)-3(x+5)
       = (x - 3)(x + 5)
       
x = 3 and x = -5
 
sum = -b/a 
        = -2

product = c/a 
             = -15 
  
sum of roots = -5 + 3
                     = -2
 
product of roots = (-5) * 3
                          = -15 
           

Answer 2

x^2 + 2x - 15 = 0
x^2  +  5x - 3x  - 15 = 0
x  [ x + 5 ] - 3 [ x + 5 ] = 0
So,
x = -5 & x = 3
So,let the zeroes of this quadratic polynomial be α=-5 & β=3

Now,
Sum of zeroes = α+β = -b / a.
And,
Product of the zeroes = αβ = c/a

Now,
here a = 1 , b = 2 and c = -15.

Now, to verify

LHS = α+β = -5 + 3 = -2
RHS = -b/a = -[2] / 1= -2.
∴ LHS = RHS
Hence verified for the sum.

Now, for the products.

LHS =αβ= -5 * 3 = -15
RHS = c /a = -15 / 1 = -15
∴ LHS = RHS
Hence, verified for the products.