If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( x )
x = 0
x = 0
x = 0
x in (-oo:0) U (0:+oo)
4/x-9 = 5*x // - 5*x
4/x-(5*x)-9 = 0
4/x-5*x-9 = 0
4*x^-1-5*x^1-9*x^0 = 0
(4*x^0-5*x^2-9*x^1)/(x^1) = 0 // * x^2
x^1*(4*x^0-5*x^2-9*x^1) = 0
x^1
4-5*x^2-9*x = 0
4-5*x^2-9*x = 0
DELTA = (-9)^2-(-5*4*4)
DELTA = 161
DELTA > 0
x = (161^(1/2)+9)/(-5*2) or x = (9-161^(1/2))/(-5*2)
x = (161^(1/2)+9)/(-10) or x = (9-161^(1/2))/(-10)
x in { (161^(1/2)+9)/(-10), (9-161^(1/2))/(-10)}
x in { (161^(1/2)+9)/(-10), (9-161^(1/2))/(-10) }
| -14=-4x | | 21-5q=4 | | X/9=3/x | | -14=14x | | 12x+5=2x+5 | | 23.9=-22.4-n | | 15x+18=23x-8 | | f(x+h)=x(20-x) | | 8x^3-12X^2y+6xy^2-y^3=0 | | 6-4x+2=5x-1 | | -1/7b-4=3 | | 13x+7=10x+11 | | 253=11+11m | | f(-x)=6x^2+2x-12 | | -3(5n-5)=-105 | | 6(x+8)=5-4 | | 5/2t=20 | | 0.01/3.13x100 | | 9-(3z-9)=6-4z | | 16=r^8 | | 24x^4-36X^3y+18x^2y^2-3xy^3=0 | | -139=-7-3(-4+6a) | | 5y+2x=7 | | A+140-40=310 | | 1/3p-5=-2 | | 10b+28=88 | | 3x=(500/5) | | 7x+6(x+6)=-8+6(3x+4) | | 3(x-4)=-(7-2x) | | 10+3(x-13)=-5(1-5)+14 | | -4(2-h)-3=6+3(2h+1) | | 13(a-11)=117 |