(-x的平方+2x+15)÷(x+3)

问题描述:

(-x的平方+2x+15)÷(x+3)

(-x的平方+2x+15)÷(x+3)
=-(x²-2x-15)÷(x+3)
=-(x-5)(x+3)÷(x+3)
=-(x-5)
=-x+5