107k views
4 votes
Solve the following system of equations by substitution: 5x + 2y = 14 y = x – 7 Question 11 options: (–3, 4) (2, –5) (4, –3) (–5, 2)

1 Answer

4 votes
To solve this system using substitution, start by writing them next to each other. You can see that the y value is already isolated with its own value (x - 7).

So, since y equals that expression, you can substitute it into your first given equation for the y.
This leaves you with:
5x + 2(x - 7) = 14

Then, use the distributive property to simplify your equation.
This ends up with:
5x + 2x - 14 = 14

Combine like terms by adding the coefficients in front of your x’s.
This results in:
7x - 14 = 14

Begin to isolate your variable by adding 14 to both sides.
This leaves you with:
7x = 28

Divide both sides by 7 to find the value of x in your solution.
This results in:
X = 4
So you know that the x value in your final ordered pair will be a 4.
At his point you could eliminate answer options and find the correct one, however to find your y value:

Substitute in your x to the simplest equation you were given in the system at the beginning.
This would be y = x - 7
Plugging in the value leaves you with:
y = 4 - 7
Subtract to find your final answer.
4-7= -3

So your y value is -3.

This makes your final ordered pair option C. (4, -3)
User Joseph Mark
by
8.2k 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