Answer: x=2, and cannot be equal to -5, -2 or 0
Explanation:
Basically, (x^2+7x+10)=(x+2)(x+5)
The denominator cannot be 0, so it cannot be equal to -5 or -2
It also obviously cannot be 0, or else the second part would be equal to 0, and the problem would be invalid.
From noticing that 3x+15=3(x+5), we can change the equation to
(6x/3)/(x^2+2x)/(x+2)
Simplifying it further, we get that x^2+2x=x(x+2)
(6x/3)/x
6/3
2