If the graphs of the equations \(5x-y=19\) and \(x+y=5\) intersect at \((p,q)\), what is the value of \(p-q\)?
Answer and explanation
Correct answer: 3
In the graphical method, the intersection point of the two lines represents the common solution of both equations. From \(x+y=5\), we get \(y=5-x\). Substituting this in \(5x-y=19\) gives \(5x-(5-x)=19\), so \(6x=24\) and \(x=4\). Consequently, \(y=1\), hence \((p,q)=(4,1)\) and \(p-q=4-1=3\). Therefore, option C is correct. Exam tip: the coordinates of the intersection of two lines give the simultaneous solution of their equations.
Frequently asked questions
What is the correct answer to this question?
3
Why is this the correct answer?
In the graphical method, the intersection point of the two lines represents the common solution of both equations. From \(x+y=5\), we get \(y=5-x\). Substituting this in \(5x-y=19\) gives \(5x-(5-x)=19\), so \(6x=24\) and \(x=4\). Consequently, \(y=1\), hence \((p,q)=(4,1)\) and \(p-q=4-1=3\). Therefore, option C is correct. Exam tip: the coordinates of the intersection of two lines give the simultaneous solution of their equations.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Pair of Linear Equations in Two Variables. Topic: Graphical method of finding solutions..
