Question

凱蒂

1）
（x+1)(x+2)(x+3)(x+6)-15x²
2)
(xy+1)(x+1)(y+1)+xy
3)
x²+xy-2y²-2x+5y-3
*因式分解

Answer 1

Call me Bravo

For your reference

凱蒂

can't understand

Call me Bravo

Which one? Which steps?

凱蒂

all three,
I can't understand how do you get the answers

凱蒂

also the first steps you wrote