WASHINGTON (Reuters) - President Donald Trump on Wednesday proposed slashing the U.S. tax rate on corporate and pass-through business profits to 15 percent from 35 percent or more, while also offering tax cuts to average Americans in a rough outline of his tax policy goals. A one-page summary of his proposals, released at a White House briefing, said Trump also wants to reduce the number of tax brackets to three from seven, double the standard deduction that Americans can claim on their tax returns and repeal the estate tax and alternative minimum tax. Under U.S. law, only Congress can make major tax law changes. Lawmakers initially greeted Trump’s plan as a starting point for further discussion on overhauling the tax code. 