Avoid lines with more than 80 characters. For long instructions, you should better rewrite

D := divide((k*(k-i)*(SR[k][i])*(SR[k][k])
            -(i+1)*(SR[k][k-1])*(SR[k][i+1])),delt[k]);

into

left  == k * (k-i) * SR[k][i] * SR[k][k];
right == (i+1) * SR[k][k-1] * SR[k][i+1];
D := divide (left - right, delt[k]);

Add spaces around the main operators to ease readability. For instance the expression

a:=b[0]*b[2]/c[0]-a[3]*b[0]^2*c[5]+a[6]*a[7]-b[8]^10;

should better be written

a := b[0]*b[2]/c[0] - a[3]*b[0]^2*c[5] + a[6]*a[7] - b[8]^10;

Align operators when useful for readability. For instance write

blah == 2;
boe  == 3;

Function and macro names should be meaningful and written in English.