Asalesman weekly salary in calculated using function p(x)=0.09x+c, where x is that week’s revenue in dollars and c is a constant. find c, if on the week when salesman sold goods on $1570 his salary was $490.30.

Step 1:

Put the information given in the word problem into the equation p(x)=0.09x+c. So plug in 1,570 for x and 490.30 for p(x).

490.30 = 0.09 (1,570) + c
     490.30 = 141.3 +c
   -141.3      -141.3

     349 = c

Step 2: Check your work!

490.30 = 0.09 (1,570) + 349
490.30 = 141.3 + 349
490.30 = 490.30 

B, 0.4 repeats so it is rational and square root of 16 is 4 so that is rational as well.