Question 1148137
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it is equal to  {{{7^(x+3)}}} - {{{7^(x+1)}}} = {{{7^3*7^x - 7*7^x}}} = {{{(7^3-7)*7^x}}} = {{{7*(7^2-1)*7^x}}} = {{{7*48*7^x}}} = {{{336*7^x}}}.    <U>ANSWER</U>
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