x²-64y²分之2x 减 x-8y分之1

问题描述:

x²-64y²分之2x 减 x-8y分之1

通分:[2x-(x+8y)]/(x+8y)(x-8y)=(x-8y)/(x+8y)(x-8y)=1/(x+8y)
望采纳,谢谢

原式=2x/(x²-64y²)-(x+8y)/(x²-64y²)=(2x-x-8y)/(x²-64y²)=1/(x+8y);

x²-64y²是用平方差

x²-64y²分之2x 减 x-8y分之1= 2x-(x+8y)/(x²-64y²)=(x-8y)/(x+8y)(x-8y)=1/(x+8y)

2x/(x²-64y²) - 1/(x-8y) 根据公式:a²-b²=(a+b)(a-b)
=2x/(x+8y)(x-8y) - 1/(x-8y) 通分
=2x/(x+8y)(x-8y) - (x-8y)/(x+8y)(x-8y)
=(2x-x+8y)/(x+8y)(x-8y)
=(x+8y)/(x+8y)(x-8y)
=1/(x-8y)