If it's not what You are looking for type in the equation solver your own equation and let us solve it.
d in (-oo:+oo)
-7*d = 21/8 // - 21/8
-7*d-(21/8) = 0
-7*d-21/8 = 0
-7*d-21/8 = 0 // + 21/8
-7*d = 21/8 // : -7
d = 21/8/(-7)
d = -3/8
d = -3/8
| w/2=-1/5 | | k-7/9=-1/9 | | 8-2k=5 | | k+4=55/12 | | 1+x=9/7 | | 4-7f=11 | | 7n=28/5 | | 5/7m=5/21 | | 10+m=91/10 | | 15=b+8 | | w+10=12 | | 1/4=x+1 | | w-9=-6 | | m+2/5=57/5 | | t+10=19/2 | | t-9=-115/12 | | b/3=4/5 | | x^2=1068 | | 4x+4=1+6x | | a-2/5=43/5 | | 1+t=16/9 | | 6k=66 | | -52/7=m+4/7 | | 5/7m=5/14 | | b-7=-33/5 | | x-1=-5/12 | | w/-2=-5/6 | | t-2/5=7/20 | | -7n=-77 | | t=-3/4 | | 2=n+9 | | d+5=62/11 |