Chen uses different strategies to add. he works with the addends 4,5,6,7

choose one of churns addends use that number to write a doubles

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18

a = 3.14

b = 18

c = 18/5 or 3.6 or 3 3/5

step-by-step explanation: