Question

9(x+y)的平方—4（x--y)的平方用因式分解法做

Answer 1

9(x+y)的平方—4（旦嫌山者陆x--y)的平方模中
=[3(x+y)+2(x-y)][3(x+y)-2(x-y)]
=(5x+y)(x+5y)