Respuesta :

s^2-10s=23
add 25 to both sides to make a perfect square on the left
s^2-10s+25=23+25=48
The left hand side is a perfect square, so factor
(s-5)^2=48
s-5=sqrt(48)=+/- 4sqrt(3)
s=5 +/- 4sqrt(3)
or
s={5-4sqrt(3), 5+4sqrt(3)}