x-lungimea terenului
1/4 din x +30= 1/4 *x+ 30 = x/4 +30 -cu porumb
x- x/4+ 30 = (4x-x-120)/4= (3x-120)/4 -restul
5/8 din (3x-120)/4= (15x-600)/32 -cu grau
(3x-120)/4 - (15x-600)/32 = ( 24x-960-15x +600)/32= (9x-360)/32 -noul rest
(9x-360)/32= 1/4 *x aducem la acelasi numitor
9x-360=8x
9x-8x=360
x=360