一元二次方程x²﹣9=0的根为[ ]

A．x=3

B．x=﹣3

C．x₁=3，x₂=﹣3

D．x₁=0，x₂=3

On January 1,2007, Sneed Corporation purchased machinery costing $ 8 million with a salvage value of $1 million. For the year ended 2007, Sneed recognized depreciation expense of $ 3.2 million from the machinery using the double-declining-balance method. Should the depreciation expense be reported as an operating component in the income statement, and what is the estimated useful life of the machinery Operating expense Useful life ()①A. No 5 years ②B. Yes 4 years ③C. Yes 5 years

A. ①

B. ②

C. ③