What is the formula of the nth power expansion of (AX + by)

What is the formula of the nth power expansion of (AX + by)

The nth power expansion of (AX + by) is
C(n,0)(ax)^n(by)^0+C(n,1)(ax)^(n-1)(by)^1+.C(n,r)(ax)^(n-r)(by)^r+.+C(n,n)(ax)^0(by)^n

Please help me choose numbers from the ten numbers of "1, 2, 3, 4, 5, 6, 7, 8, 9, 10", each number can only be used once, plus sign character: + minus sign character: - multiply sign character: * division sign character: / bracket: () bracket:], the result must be equal to 9
A total of 30 combinations!

9+1/2=9.59+2/4=9.59+3/6=9.59+4/8=9.59+5/10=9.5(1+8)+2/4=9.5(1+8)+3/6=9.5(1+8)+5/10=9.5(2+7)+3/6=9.5(2+7)+4/8=9.5(2+7)+5/10=9.5(3+6)+1/2=9.5(3+6)+2/4=9.5(3+6)+4/8=9.5(3+6)+5/10=9.5(4+5)+1/2=9.5(4+5)+3/...

Find a mathematical formula, is that how many degrees is equal to a few fractions of that school

180 degrees equals π
360 degrees equals two PI
60 degrees equals 1 / 3 PI
MS has no formula

What are the mathematical formulas equal to 1
The mathematical formula of 1 is very interesting and useful. But I don't know much about it. The more, the better. For example: sin ^ 2 α + cos ^ 2 α = 1;
The reciprocal product of two numbers: xy = 1;
The zero power of nonzero number is equal to 1: m ^ 0 = 1 (m ≠ 0);

The square of sina + the square of cosa = 1
Tana times COTA = 1
SecA times CSCA = 1