Coin contains 9 gramsof nickel and 16 g of copper for a total weight of 25 g what percentage of the metal in the coin is copper

Use ratios:

Grams:Total      SF: 100 divided by 25 = 4
NICKEL=
9 grams: 25grams =  36% : 100% 
Multiply 9grams of nickel by 4 (the scale facotr) to get the percentage of nickel in the coin

COPPER=
16 grams: 25grams = 64% :100%
Multiply 16 grams of copper by 4 (the scale factor) to get the percentage of copper in the coin

ANSWER: 26% of nickel and 64% of copper is in a coin

When x =0 , y = -5
when x =1 , y = -6
when x =2 , y = -7
when x =3 , y = -6
when x =4 , y = -5
make a  chart