Question

Which are the solutions of x^2 =-7x-8

Answer 1

Answer:

x 2 + 7 x − 8 = ( x − 1 ) ( x + 8 )

Step-by-step explanation:

Given  

x 2 + 7 x − 8

Note that the sum of the coefficients is  0  

That is  1 + 7 − 8 = 0

So  x = 1  is a zero and  ( x − 1 )

a factor:  x 2 + 7 x − 8 = ( x − 1 ) ( x + 8 )

The linear factor  ( x + 8 )  can be constructed by looking at the coefficients of  

x 2  and the constant term  − 8

that we want in the product:

Since the coefficient of  x 2  is  1  in the product, we require a coefficient  

1  for  x

Since the constant term is  − 8 in the product, we require a constant  + 8

in the factor which will become  − 8  when multiplied by  − 1