函数的表达式已知，4个变量已知3个，请问应如何求解剩下的那个参数r?我使用的是solve函数，运行后结果是一大串，没有求出正确结果。求大佬指教，万分感谢！
代码如下：
clc;
clear;
syms M r y L;
L = 17;
M = 0.125;
y = 20;
equ = r*L/12*(1-1/(1+r/12)^12*y) == M;
anws = solve(equ,r)
运行后结果
anws =
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 1)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 2)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 3)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 4)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 5)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 6)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 7)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 8)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 9)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 10)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 11)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 12)
root(z^13 + (4893*z^12)/34 + (161352*z^11)/17 + (6448464*z^10)/17 + (173923200*z^9)/17 + (3334877568*z^8)/17 + (46608224256*z^7)/17 + (478300889088*z^6)/17 + (3575727783936*z^5)/17 + (18978317107200*z^4)/17 + (67768555143168*z^3)/17 + (145443888562176*z^2)/17 - (2893274595459072*z)/17 - 13374150672384/17, z, 13)
