Answer:
7.5
Step-by-step explanation:
you are trying to figure out what the equation equals so what times two equals 15? 7.5 and 15-15 equals 0
Step-by-step explanation:
[tex] {x}^{2} - 15 = 0 \\ \\ \therefore \: {x}^{2} = 15 \\ \\ \therefore \: x = \pm \sqrt{15} \\ \\ \therefore \: x = \sqrt{15} \: \: or \: \: x = - \sqrt{15} \\ \\ \therefore \: x = \{ - \sqrt{15}, \: \: \sqrt{15} \} \\ [/tex]
henc, there are two real solutions.