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Solve the system of linear equations by elimination. Check your solution.

3x - 4y = 17
7x - 4y = 13​

User Lindsey
by
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1 Answer

13 votes

Answer:

( - 1, - 5)

Explanation:

Elimination Method:

  • A method for solving a system of linear equations where you add or subtract equations to eliminate a variable
  • Eliminating one variable by combining two equations with a common term with adding or subtracting

Multiply the second equation by -1, then add the equations together.

(3x−4y=17)

−1(7x−4y=13)

Becomes:

3x−4y=17

−7x+4y=−13

Add these equations to eliminate y:

−4x=4

Then solve−4x=4for x:

−4x=4

-4x / -4 = 4/-4 (Divide both sides by -4)

x= −1

Now that we've found x let's plug it back in to solve for y.

Write down an original equation:

3x−4y=17

Substitute−1forxin3x−4y=17:

(3)(−1)−4y=17

−4y−3=17(Simplify both sides of the equation)

−4y−3+3=17+3(Add 3 to both sides)

−4y=20

-4y/ -4 = 20/ -4 (Divide both sides by -4)

y=−5

Answer:

x=−1 and y=−5

User Sean Ford
by
4.4k points