Question

Which of the following is the correct expansion of the binomial (x + y)^6?

Answer 1

Looking at Pascal's triangle (not my picture!), the pattern is we start with x^6*1+x^5*y*6 etc. while subtracting 1 exponent from x and adding 1 to y every time, ending up with x^6+6x^5y+15x^4y^2+20x^3y^3+15y^4x^2+6y^5x+y^6