(3a+2b-7)-(4b-10) need help bad

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Brady has a 20 year fixed rate mortgage for $215,500 with monthly payments of 1,305.89.the annual interest rate is 4%. what is the total cost of the principal and interest for this loan rounded to the nearest dollar

What are the constants in this expression? -10.6+9/10+2/5m-2.4n+3m

The sales totals at macy's food store have increased exponentially over the months. which of these best shows the sales in the first three months?