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Mathematics · Pair of Linear Equations in Two Variables · NCERT Examples

Example 4

A complete, independently verified solution for NCERT Example 4.

Mathematics · Chapter 3 · NCERT Examples

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Verified NCERT questions and solutionsSolutions are checked independently and follow the supplied NCERT chapter edition.

NCERT Example

Example 4

substitution method

Solve 7x − 15y = 2 and x + 2y = 3 by substitution.

Solution

x=3−2yx=3-2y
7(3−2y)−15y=2⇒−29y=−197(3-2y)-15y=2\Rightarrow-29y=-19
y=1929,x=3−3829=4929y=\frac{19}{29},\qquad x=3-\frac{38}{29}=\frac{49}{29}
7(4929)−15(1929)=2,4929+2(1929)=37\left(\frac{49}{29}\right)-15\left(\frac{19}{29}\right)=2,\quad\frac{49}{29}+2\left(\frac{19}{29}\right)=3

Final answer

x=4929,y=1929x=\frac{49}{29},\qquad y=\frac{19}{29}