Question

I need help

Answer 1

Answer:

a)  x =3 and x=5

c)  x =-1 and $x = \frac{-7}{3}$

i)  x =0 and  $x = \frac{-9}{2}$

Step-by-step explanation:

a)

Given that the quadratic equation

    x² - 8x +15 =0

The factors of 15 = 5 × 3

   x² - 5x -3x +15 =0

  x(x -5) -3(x-5) =0

  (x-3)(x-5) =0

x =3 and x=5

c)

  3 x² + 10 x +7 =0

⇒   3x² + 3x + 7x +7 =0

⇒   3x (x +1) +7(x+1) =0

⇒  (x+1) ( 3 x +7) =0

⇒  x =-1 and $x = \frac{-7}{3}$

i)

     2 x ² + 9 x =0

⇒ x( 2 x + 9) =0

⇒ x =0 and 2 x = -9

⇒ x =0 and  $x = \frac{-9}{2}$