Question

Which of the following is the solution to the quadratic equation ² - 10x + 21 = 0?

c
O a. x = 7, 3
O b. x =
O c. x = 7,3
d. x =
-7, -3
- 7,3

Answer 1

x= 7 and x=3

Explanation:

equation:

`{ x}^(2) - 10x + 21`

a= 1 b=-10 c=21

`{b}^(2) - 4(a)(c)`

`{( - 10)}^(2) - 4(1)(21) = 16 > 0`

thus, x1 =

`( - b - √(16) )/(2a) = (10 - √(16) )/(2 ) = 3`

x2 =

`( - b + √(16) )/( 2a) = ( 10 + √(16) )/(2) = 7`