What happens to the demand curve when an "across the board" change in demand occurs?

The difference of 2 numbers is 21 and the quotient of the equation is 4 then what are the two numbers?

Which value of c would make he following expression completely factored? 8x+cy

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.