Evan has $0.45 worth of pennies and nickels. He has a total of 21 pennies And Nickels All together. Determine the number of pennies in the number of nickels that Evan has.

first of all you to multiple the decimal number by 100 to get a normal number.

o. 45. 100 = 45

x = number of pennies

y = number of nickels

x+y = 21

1x + 5y = 45

x + y = 21

y = - x + 21

1x + 5 (-x+21) = 1x-5x+105 = - 4x+105

105 % - 4 = the number of x

to find the number of y you have to minus the number of x from 21.