Question

（x-二分之一y-1）（x-二分之一y+1）-（x-二分之一y-1）的平方，其中x=1.7，y=3.9 过程给出来，谢谢了

（x-二分之一y-1）（x-二分之一y+1）-（x-二分之一y-1）的平方，其中x=1.7，y=3.9
过程给出来，谢谢了

Answer 1

√18除以√8
=√(18÷8)
=√(9/4)
=3/2

√0.4乘以√3.6
=√(0.4×3.6)
=√1.44
=√1.2²
=1.2

√3分之2乘以√8分之27=
=√(2/3×8/27)
=√(16/81)
=4/9

√2除以3√40
=(1/3)√(2÷40)
=(1/3)√(1/20)
=(1/3)√(5/100)
=(1/3)(√5)/10
=(√5)/30

Answer 2

原式=(x-1/2y)²-1²-[(x-1/2y)²-2(x-1/2)+1]
=(x-1/2y)²-1²-(x-1/2y)²+2(x-1/2y)-1
=2x-y-2
=3.4-3.9-2
=-2.5