Question

Solve x² + 5x - 300 = 0.

Answer 1

Method to find solution of a quadratic equation by factorisation:
To find the solution of a quadratic equation by factorization method we use following  steps:
Write the given quadratic equation in standard form ax² + bx + c =0, and find the values of a, b and c.
Multiply a and c and split ac into prime factors. Then find two numbers p and q such that p-q = b  (if Sign of c is negative -ve).
Write the constant b of ax² + bx + c =0, as (p-q) and then factorise it.
Equate each factor to zero  and find the values of x.
SOLUTION:

GIVEN:
x² +5x -300 = 0
x² + 20x -15x -300= 0
x( x +20) -15(x +20)= 0
(x +20)(x- 15)= 0
(x +20)= 0   or  (x- 15)= 0

x= -20  or  x= 15

HOPE THIS WILL HELP YOU....

Answer 2

x^2 + 5x - 300
x^2 + 20x - 15x - 300
x(x + 20) -15(x + 20)
(x + 20)(x - 15)
so,
       x = - 20
and
       x = 15