Estimate the sum or difference of 23/40 11/30

23/40+11/30=68/120+44/120=110/120=11/12

23/40-11/30=68/120-44/120=24/120=6/30=2/10=0,2

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