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)
y = (-5/4)*x^4 // - (-5/4)*x^4
y-((-5/4)*x^4) = 0
(5/4)*x^4+y = 0
5/4*x^4 = -y // : 5/4
x^4 = -4/5*y
x^4 = -4/5*y // ^ 1/4
abs(x) = (-4/5)^(1/4)*y^(1/4)
x = (-4/5)^(1/4)*y^(1/4) or x = -((-4/5)^(1/4)*y^(1/4))
x in { (-4/5)^(1/4)*y^(1/4), -((-4/5)^(1/4)*y^(1/4)) }
| y=-5/4x=4 | | 4m^2+3=303 | | x+x-6+2(x-6)+1=67 | | 5f+3-2y+4-f= | | 49+7(-7)= | | 4x-6+12+1=67 | | (x+0.9)(2x+1.8)-1.62=2x^2+2.7x | | 8(y-7)+18y=2y+140 | | 7(x-4)=4x+7 | | x/8-1/2=x/6-2 | | 4-3/5 | | 5s=s+1-2s | | 49.75+0.50m= | | 2-5t-3=34 | | [x-5][-3]=18 | | 2x+5x-6+7= | | x+.08x=20 | | -7/3r-2=3 | | (2x+9)(81x+5x+3)= | | 3m=n | | 0.08(y-7)+0.18y=0.02y+1.4 | | 60-16t^2=t | | 7x-28=4x+7 | | X^2+y^2-16=0 | | 8/k-7=6/k | | 8x^4-4x^3-84x^2=0 | | 9k-8+24=52 | | (2/5x)(-7/20x)=4 | | 4/3*3.14*27 | | 4/9x8/10 | | 8y+5-7y=-4 | | 2y^2+y-2=0 |