Question

Solve by completing the square w^2-10w+21=0

Answer 1

The solutions are w=7, w=3

Explanation:

we have

`w^2-10w+21=0`

Group terms that contain the same variable and move the constant term to the right side

`w^2-10w=-21`

Complete the square

`w^2-10w+5^2=-21+5^2`

`w^2-10w+25=-21+25`

`w^2-10w+25=4`

Rewrite as perfect squares

`(w-5)^2=4`

take square root both sides

`w-5=(+/-)2`

`w=5(+/-)2`

`w_1=5(+)2=7`

`w_2=5(-)2=3`

therefore

The solutions are w=7, w=3