Question 1187362
<pre>
{{{system(matrix(5,7,

y,""="",Ax^2,""+"",Bx,""+"",C,
"","","","","","","",
4,""="",A(5)^2,""+"",B(5),""+"",C,
2,""="",A(11)^2,""+"",B(11),""+"",C,
-4,""="",A(21)^2,""+"",B(21),""+"",C))}}}

{{{system(matrix(5,7,

y,""="",Ax^2,""+"",Bx,""+"",C,
"","","","","","","",
4,""="",25A,""+"",5B,""+"",C,
2,""="",121A,""+"",11B,""+"",C,
-4,""="",441A,""+"",21B,""+"",C))}}}

So solve the 3x3 system of equations for A, B, and C and substitute in


{{{matrix(1,7,y,""="",Ax^2,""+"",Bx,""+"",C)}}}

Edwin</pre>