If it's not what You are looking for type in the equation solver your own equation and let us solve it.
a in (-oo:+oo)
2*a+7 = -13 // + 13
2*a+7+13 = 0
2*a+20 = 0 // - 20
2*a = -20 // : 2
a = -20/2
a = -10
a = -10
| 7d+9=-19 | | 2b-10=-10 | | -2m+10=-12 | | 5t+3=-52 | | -7b+2=16 | | 10-3w=7 | | 5+5a=55 | | p-26=-38 | | -7m+2=51 | | -6-6w=48 | | 4-5b=-1 | | 5k+3=13 | | 3a+1=-14 | | 9+4t=-19 | | 1+5k=51 | | 8-7k=71 | | 6x-8=-56 | | 3b*b=68 | | w+2=-3 | | 7n-3=-3 | | -2a+4=-16 | | 3+4w=-5 | | 5a+1=21 | | -2+7x=-37 | | -5w+9=54 | | 6+5w=41 | | -3w+1=28 | | 5+3k=8 | | 2+3n=-16 | | 3+6n=51 | | 2+4/9x=-12 | | -(4y+4)-(-3y-8)=2 |