⇔ Consider the first digit = a, and the second digit = b
≡ We know that:
⇔ [tex](a+b)=8[/tex]
⇔ [tex]a^{2}+b^{2}=50[/tex]
≡ Solution:
⇒ [tex]a^{2}+b^{2}=(a+b)^{2}-2ab[/tex]
⇒ [tex]50=(8)^{2}-2ab[/tex]
⇒ [tex]2ab=64-50[/tex]
⇒ [tex]2ab=14[/tex]
⇒ [tex](a).(b)=7[/tex]
⇔ Cause a × b = 7, there are 2 option the value of ab that:
∴ a = 1, b = 7 → 17
∴ a = 7, b = 1 → 71
