The equations of 2 regression lines are
8x - 10y + 66 = 0 , 40x - 18y - 214 = 0
Obtain the standard deviation of Y is standard deviation of X is 3
Your 2 equations $\displaystyle 8x - 10y + 66 = 0 , 40x - 18y - 214 = 0$ need to be put in the form $\displaystyle y=a+bx $ as this form helps us identify parameters like the standard deviation and the mean.
Note that for $\displaystyle y=a+bx $
$\displaystyle b = r\times \frac{s_y}{s_x}$
$\displaystyle a = \bar{y} -b\bar{x}$
so do you have any additional information?