Question

Once you have a single variable isolated in one of the two equations in a system, the second step of using substitution to solve the system of equations is to __________.
A. solve for the second variable in the other equation
B. solve for the second variable in the same equation
C. substitute the expression equal to the solved variable into the other equation D. substitute the expression equal to the solved variable into its original equation

Answer 1

C

Answer 2

because if you do it in the original, you'll get something like 2=2
same goes for solving for the second in the same equ

solving for the second in the other equation will be your next step