He says some Asian currencies, including China's,are undervalued, but he says that steps to increase Asia's domestic demand will result in a gradual increase in their value.

VOA: standard.2009.11.13

Then go to the x equation and demand that this be equal to the desired x value and find the time.

然后列出关于 x 的方程,令这个式子等于给定的 x,并求出时间

耶鲁公开课 - 基础物理课程节选

He would like to move into the formal economy so that he can serve larger customers, who demand value-added tax receipts.

FORBES: This Money Won't Buy Happiness

Ultimately the pricing is a function of the demand and value that customers have for that service.

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Interest in things such as green products and healthy foods will continue to grow in a post-crisis world, but customers will be less willing to pay a premium for them, and will demand more value for money when they do.

ECONOMIST: Consumer psychology