已知x=3-2y,求3根号x-2y÷根号4x²-16y²的值

题目

已知x=3-2y,求3根号x-2y÷根号4x²-16y²的值

答案

x=3-2y
x+2y=3
3根号x-2y÷根号4x²-16y²
=3(√x-2y)÷[2(√x-2y)(√x+2y)]
=3/2(√x+2y)
=3/2*(√3)
=√3/2