expand the brackets,
leaving you wit 3x^2+11x+15=7,
take 7 to the other side of the equal sign by subtracting the LHS equation by 7,
leaving you wit, 3x^2+11x+8=0,
using the quadratic formula,
x=(-b) (+-) ((sqrt((b^2)-(4*a*c)))/2a)
(please if the quadratic equation is not clear to you pls do search for it)
then it will give you values for x.
(do corrct me if im wrong)
Algebraically only? Better use technology. Plot y = 3x^2 +14x +15 and y = 7/x and look for point of intersection, if it is x(x+3)(3x+5) =7.
If it is only (x+3)(3x+5) =7, use quadratic formula.