Solve 2x + 5y = 11 and x - 3y = -11 by substitution.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Solve and by substitution.
Need a reminder? The key ideaShow
Substitution: write one letter in terms of the other and put it into the second equation. Elimination: make the coefficients of one letter match, then add or subtract the equations. Always put the answer back into both equations. If both letters vanish, means infinitely many solutions and a false statement means none.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. One letter in terms of the other. From we get .
Step 2. Substitute. , so and .
Step 3. Solve. , and then .
Check. and .
Answer: and .
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