If it's not what You are looking for type in the equation solver your own equation and let us solve it.
k in (-oo:+oo)
k/(-6) = 28 // - 28
k/(-6)-28 = 0
-1/6*k-28 = 0 // + 28
-1/6*k = 28 // : -1/6
k = 28/(-1/6)
k = -168
k = -168
| 28x^4+21x^6+5x-7=0 | | -2(-2)+y=5 | | -30x+3(-1.5+3x)=-1.5 | | -(x+3)-6=-7 | | 4x+2x+x=21 | | -2(-1)+y=5 | | 2x-(2+8.6x)=-20-9.6x | | 7x+5x+4=88 | | 6x^2-x-77=0 | | 10x=2x-6x+7 | | 2x+.5x+90=180 | | 4x/5+3(1/2+4x/2)=7/2+11x/5 | | -2(a+5)-4=-3 | | r+15=26 | | 2x+1/2x+90=180 | | 3x-(-1.6-4.6x)=-1.4+11.6x | | -20=-5/3v | | 54x^4=250x | | j/3=48 | | 35x^2+98=0 | | k/3=18 | | (3x/4)-3=9 | | x+0.2x=22287 | | -3c-(-4c)+1=21 | | -9/10k=72 | | -5(x+7)=-5t-6t | | 2x+6+2x-6+x=180 | | w+41=64 | | x-6/x-1=5/12 | | 12.4+8.6x=-3.4(-3x-4) | | -25=5/6r | | 8x+2+9x+3+90=180 |