What must be included in an algebraic expression?

A an equals sign
B at least one variable
C one or more numbers
D more than one operation

B. you need atleast one variable for an algebraic expression.

an equals sign would make it an algebraic equation,

just a coefficient and a variable is the most basic algebraic expression. you don't need anything other than those for an expression. you can have more than one number, and more than one operation, but they don't have to be there.

Step-by-step explanation:

i hope this helps :))

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