105k views
4 votes
Solve by substitution when equations are solved for a variable. y = x +3 y = 2x + 12

1 Answer

4 votes

\begin{cases}y=x+3\Rightarrow\text{ Equation 1} \\ y=2x+12\Rightarrow\text{ Equation 2}\end{cases}

To solve the given system of equations by substitution method, we can do the following steps:

Step 1: We substitute the y-value of one equation into the other equation. For example, we replace the value of y from Equation 1 into Equation 2.


\begin{gathered} y=2x+12\Rightarrow\text{ Equation 2} \\ x+3=2x+12 \end{gathered}

Step 2: We solve for x the resulting equation.


\begin{gathered} x+3=2x+12 \\ \text{ Subtract 3 from both sides} \\ x+3-3=2x+12-3 \\ x=2x+9 \\ \text{ Subtract 2x from both sides} \\ x-2x=2x+9-2x \\ -x=9 \\ \text{ Multiply by -1 from both sides} \\ -x\cdot-1=9\cdot-1 \\ \boldsymbol{x=-9} \end{gathered}

Step 3: We replace the value of x in any of the initial equations. For example, in Equation 1:


\begin{gathered} y=x+3 \\ y=-9+3 \\ $$\boldsymbol{y=-6}$$ \end{gathered}

Therefore, the solution of the given system of equations is the ordered pair (-9,-6).

User Prosto Trader
by
7.6k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories