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)
(-7/10)*k+14 = -21 // + 21
(-7/10)*k+14+21 = 0
35-7/10*k = 0 // - 35
-7/10*k = -35 // : -7/10
k = -35/(-7/10)
k = 50
k = 50
| -89=8(x-7)+3x | | 9x+9=6x+15 | | a(x-b)=x | | 3x+6=x+2(4+x) | | -4(1-6n)=-100 | | (2X+13)3-(X-4)4=2 | | -1m+9=0 | | (x+5)+(2x-3)=96 | | x-5=-4x-2 | | (2x+1)/7-(x-1)/2=(5x-1)/14-(x-2) | | y^2+7y+18=0 | | x^3-11x-18=0 | | (X-3)4-(X-7)6=1 | | 4x+(x-10)=180 | | -8(-1+8n)=264 | | 2(2x+10)=(4x+17) | | 4(9x-7)=2x(1+5x)-(1-x) | | 144-8x=8x+16 | | (2x+5)+(5x-79)=122 | | 5x-20=x+4(5+x) | | X-(13X-X)/3=(X+2)/6 | | 4x^2-10x= | | 1/2a-1/3a=-2 | | P=R/B | | 2(2x+10)=4x+17 | | 2x/7+1/7-x/2-1/2=5x/14-1/14-(x-2) | | 3x(2x-14)=-4(3x+7)-x | | 4x+3-2x=-x-(-3x+3) | | -91=-7(8-m) | | 2(2x+10)=4x-17 | | x+6/3=9 | | -10=4x+6 |