How do i solve for a in this equation?
1-a7 = 0.5(1-a20)
Putting it into standard form a20-2a7+1=0
By observation a=1 is one solution, you could long divide a-1 into the equation and solve your new equation but that would be extremely tedious and probably not expected of you. Have you learnt Newton's method - Wikipedia, the free encyclopedia for solving equations?