" The value of "sum_(r=0)^(20)50-rC_(6)" is equal to: "

sum_(r=0)^(20).^(50-r)C_6

If the graph of non-constant function is symmetric about the point (3,4), then the value of sum_(r=0)^(6)f(r)+f(3) is equal to

The value of sum_(r=0)^n(a+r+a r)(-a)^r is equal to

The value of sum_(r=0)^(n)r(n-r)(nC_(r))^(2) is equal to

The value of sum_(r=0)^(20)r(20-r)(^(20)C_r)^2 is equal to 400^(39)C_(20) b. 400^(40)C_(19) c. 400^(39)C_(19) d. 400^(38)C_(20)

The value of sum_(r=0)^(20)r(20-r)( ^(20)C_r)^2 is equal to ?

The value of sum_(r=0)^(40)rC(40,r)C(30,r)

If the graph of non-constant function is symmetric about the point (3,4), then the value of sum_(r = 0)^6 f(r) + f(3) is equal to

The value of sum int_(r=1)^(r=10)rC(10,r) is