Which is a variable expression for the word phrase? the product of 3 and a number decreased by 7
a. 3n + 7
b. 7 – 3n
c. 3n – 7
d. 7n – 3

could you reply to this with the question so i can ?

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