SOLUTION: 1. Solve by the elimination method 5r-7s=-3 7r+5s=55

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Question 227306: 1. Solve by the elimination method

5r-7s=-3
7r+5s=55
Answer by drj(1380) About Me  (Show Source):
You can put this solution on YOUR website!
1. Solve by the elimination method

5r-7s=-3 Equation A
7r%2B5s=55 Equation B.

Step 1. Multiply by 5 in Equation A and Multiply by 7 in Equation B to eliminate the s-terms after adding the Equations now given below:

25r-35s=-15
49r%2B35s=385

Step 2. Adding the above equations yield the following.

74r=370

Divide by 74 by both sides of the equation

74r%2F74=370%2F74

r=5

Step 3. Substitute r=5 into Equation A 5r-7s=-3

5%2A5-7s=-3

25-7s=-3

Add 7s+3 to both sides of the equation

25-7s%2B7s%2B3=-3%2B7s%2B3

28=7s

Divide by 7 to both sides of the equation

28%2F7=7s%2F7

4=s

Step 4. Substitute r=5 and s=4 into 7r%2B5s=55

7%2A5%2B5%2A4=55

55=55

Step 5. ANSWER: r=5 and s=4

I hope the above steps were helpful.

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Good luck in your studies!

Respectfully,
Dr J