If it's not what You are looking for type in the equation solver your own equation and let us solve it.
x in (-oo:+oo)
0 = (100*(0.85-x))/0.5 // - (100*(0.85-x))/0.5
0-((100*(0.85-x))/0.5) = 0
-200*(0.85-x) = 0
0.85-x = 0 // - 0.85
-x = -0.85 // * -1
x = 0.85
x = 0.85
| 10a+30b=60 | | (8x+3)*(x^2-x-3)-(6x^2-4)=y | | 0=((0.85-x)*100)/(0.85-0.35) | | 0=((0.85-x)100)/(0.85-0.35) | | 10x+9=0 | | x^3+2x^2-81x+162=0 | | 0=((0.85-x)/(0.85-0.35))100 | | 0=(0.85-x)100 | | 9a+15=40 | | 26x-6-15x+2=24x-3-13x+13 | | 3x^2-78x+56=0 | | 7-4x=2x-11 | | 3*[-4/7]=c | | 3*[-4/7]= | | -4/7c=3 | | (3x)+(3)(2x)=90 | | A^2=2a+15 | | a^2+4a+4=25-11a^2 | | 7z+20=41 | | 5(2x+1)+8= | | 2/x-7/30 | | (x-644)/5 | | 5x-2=-16 | | 7x-2(-x-16)=-58 | | 8x+8=2x+14 | | 7x-2(-5x+8)=11 | | 3y+10=13 | | x^5-6x^2-18x+20=0 | | 3/5-5/8= | | 3/5*5/8= | | 2.1x-3.3=3.15-2.2x | | 3/5x5/8 |