If (2x+3y=13) and (mx-3y=17) have solution (x=5), what is (m)?
Answer and explanation
Correct answer: 4
Since the solution has \\(x=5\\), substitute it into the first equation: \\(2(5)+3y=13\\), so \\(10+3y=13\\) and \\(y=1\\). Substituting \\(x=5\\) and \\(y=1\\) into the second equation gives \\(5m-3=17\\), hence \\(5m=20\\) and \\(m=4\\). Therefore, option B is correct. Exam tip: When a solution coordinate is given, substitute the coordinates into both equations to determine the unknown parameter.
Frequently asked questions
What is the correct answer to this question?
4
Why is this the correct answer?
Since the solution has \\(x=5\\), substitute it into the first equation: \\(2(5)+3y=13\\), so \\(10+3y=13\\) and \\(y=1\\). Substituting \\(x=5\\) and \\(y=1\\) into the second equation gives \\(5m-3=17\\), hence \\(5m=20\\) and \\(m=4\\). Therefore, option B is correct. Exam tip: When a solution coordinate is given, substitute the coordinates into both equations to determine the unknown parameter.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Pair of Linear Equations in Two Variables. Topic: Algebraic methods: Substitution method and Elimination method..
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