If it's not what You are looking for type in the equation solver your own equation and let us solve it.
n in (-oo:+oo)
(n/2)*(8*n-4) = 90 // - 90
(n/2)*(8*n-4)-90 = 0
1/2*n*(8*n-4)-90 = 0
1/2*n*(8*n-4)-90 = 0
4*n^2-2*n-90 = 0
4*n^2-2*n-90 = 0
2*(2*n^2-n-45) = 0
2*n^2-n-45 = 0
DELTA = (-1)^2-(-45*2*4)
DELTA = 361
DELTA > 0
n = (361^(1/2)+1)/(2*2) or n = (1-361^(1/2))/(2*2)
n = 5 or n = -9/2
2*(n+9/2)*(n-5) = 0
2*(n+9/2)*(n-5) = 0
( 2 )
2 = 0
n belongs to the empty set
( n+9/2 )
n+9/2 = 0 // - 9/2
n = -9/2
( n-5 )
n-5 = 0 // + 5
n = 5
n in { -9/2, 5 }
| 3y+4=40-3y | | 1/2-y=9 | | S=sg+3u | | -6x+2-2x=-2x+14-2x | | -8/4--8/2=x | | 3/y^2-9 | | 252=-7(5x+4) | | 13+8=rt | | 3-2i+z=0 | | 5(6x+7)+2x=x+35 | | x/4-x/2=2 | | 5/2a-8=-3 | | Z(6+4i)=1 | | (9-y)(3y+2)=0 | | 6*y-4-8y=-16 | | 9x^4+320=0 | | 3*2x+1-4*x+2=0 | | K+9whenk=7 | | 16t^2-165t+87=0 | | (w*L)+(w*L)=Y+w*H | | 32r^2+8r=0 | | 5t^2-10t-120=0 | | 12b^2-28b=0 | | 7/x-16/5=38/10 | | y+8=16-y | | Tan^4(x)-9tan(x)=0 | | 2a+7a+9b= | | 2x+5(x+3)-3(x+4)=103 | | 5x-3y+4x+2y= | | X^2+9x+400=80 | | X^2+9x+400=0 | | 1/x-1/3=1/4 |