208k views
5 votes
What is the solution to the pair of equations?
y = 7x − 9
y = 3x − 1

User Mons Droid
by
3.2k points

2 Answers

3 votes

Explanation:

substitution:

7x-9= 3x-1

4x= 8

x=2

User Jeff Stock
by
3.7k points
5 votes

Answer: x = 2

Concept:

There are three general ways to solve systems of equations:

  1. Elimination: Eliminating a variable by addition or subtraction when all equations have the variable.
  2. Substitution: Combining two equations when one variable is isolated into one side.
  3. Graphing: Find the intersection point of equations to get the solution.

Here, we are going to use the method of substitution because [y] is isolated onto the left-hand side.

Solve:

Given information

y = 7x - 9

y = 3x - 1

Combine both equations by substitution

7x - 9 = 3x - 1

Subtract 3x on both sides

7x - 9 - 3x = 3x - 1 - 3x

4x - 9 = -1

Add 9 on both sides

4x - 9 + 9 = -1 + 9

4x = 8

Divide 4 on both sides

4x / 4 = 8 / 4


\boxed{x=2}

Hope this helps!! :)

Please let me know if you have any questions

User Marek Dulowski
by
3.3k points