Question

Solve the system by substitution -4x-3y=-21x=y

Answer 1

We have the system of equations:

`\begin{gathered} -4x-3y=-21 \\ x=y \end{gathered}`

We have to solve it by substitution.

The second equation gives the information to substitute, for example, x with y. We perfomr the substitution in the first equation:

`\begin{gathered} -4y-3y=-21 \\ -7y=-21 \\ y=(21)/(7) \\ y=3 \end{gathered}`

Then, with the value of y and the second equation we have:

`x=y=3`

Answer: the solution to the system is x=3 and y=3.