If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( a )
a = 0
a = 0
a = 0
a in (-oo:0) U (0:+oo)
75/a = 15 // - 15
75/a-15 = 0
75*a^-1 = 15 // : 75
a^-1 = 1/5
-1 < 0
1/(a^1) = 1/5 // * a^1
1 = 1/5*a^1 // : 1/5
5 = a^1
a = 5
a = 5
| 11x+6y=49 | | 4.2x-2.16=1.68-5.5x | | 5-(-2)=3 | | -5(x-1)+8x=7+1 | | -2/3y=-1/9 | | -9x+6+10x=-2+5 | | 4a/7=8 | | x^4-12x-13=0 | | a-2b=-11 | | 2w-4=7-7w+4w | | 15(x-7)=90 | | 5+z=3 | | =3(2X+9)+4(7-X)-12 | | 9y-5=15y-1 | | x+5x=23+1 | | x^2y^2-3xy+3=0 | | x+10+x^2=0 | | xif(1+3x)=14 | | (15-10x)=2x-3 | | 27=3(2x+5) | | (x^2+x)(x^2-x)=0 | | 4(x-1)+2x=6x-4 | | 4z-5=9 | | 8(X+11)=10(X-7) | | -2[(x+2)+(x-2)]=(x-1)-(x-3) | | (2x-3)=2x-3 | | 2tg|x-3.14/6| | | 3y=12+15 | | x=6/5*17 | | 2xsquared-4x-7=0 | | (x-2)=2x-3 | | 12/5z=11/8 |