Answer:
Subtract by 5 on both sides.
Step-by-step explanation:
x+5 = -10. if you subtract both sides by 5, you will get x+5-5=-10-5, which can be simplified to x=-15.
So you see it is the difference of 2 perfect squares
a^2-b^2=(a+b)(a-b)
so
(3b-5)^2-c^2=(3b-5+c)(3b-5-c)