Question

x2+21x-196 how can I factorise this

Answer 1

given x² + 21x -196

coefficient of x = 21

coefficient of x² = 1

and constant term = -196

we need two numbers having summation = 21 and product = 1 × ( -196) = -196

-196 = -2 × 2 × 7 × 7 = 28 × (-7)

so we can take +28 and -7 for splitting coefficient of x

x² + 21x -196

⇒ x² + 28x - 7x - 196

⇒ x( x + 28)  - 7 ( x  + 28)

⇒(x+28) ( x -7)

hence on factorization of x² + 21x -196 we get (x+28)(x-7)

Answer 2

Answer:

y

$y = 28y = - 7$