Question

Please Help!!!

Find The Number of real numbernsolutions for the equation. x^2 - 18 = 0

A. 0

B. 2

C. cannot be determined

D 1

Answer 1

Let's use the quadratic formula

`\frac{ - b( + - ) \sqrt{ {b}^(2) - 4ac} }{4a}`
a = 1, b = 0, c = -18

`\frac{ - (0)( + - ) \sqrt{ {(0)}^(2) - 4(1)( - 18)} } {4(1)} \\ (( + - ) √(72) )/(4)`
This is now split into two equations:

`( + √(72) )/(4)`
and

`( - √(72) )/(4)`
Since
`( √(72) )/(4) \\ = (6 √(2) )/(4) \\ = (3 √(2) )/(2)`
The answer is

`(3 √(2) )/(2) \: and \: ( - 3 √(2) )/(2)`
which means there are 2 real number solutions to the problem: answer B.