Question

क्लास टेंथ एनसीईआरटी मैथ चैप्टर 3 एक्सरसाइज 3.3 क्वेश्चन नंबर 2​

Answer 1

Here is your answer user.

Answer 2

AnsWer :

m = - 1.

QuestioN :

Solve 2x + 3y = 11. and 2x - 4y = - 24. and hence find the value of 'm' for which y = mx + 3.

SolutioN :

We have, Pair of Linear Equation.

$\tt \dagger \: \: \: \: \: 2x + 3y = 11. \: \: \: \: \: - (1)$

$\tt \dagger \: \: \: \: \: 2x - 4y = - 24. \: \: \: \: \: - (2)$

We have, Method to solve [ Pair of Linear Equation ]

• Elimination Method.
• Substitution Method.
• Cross multiplication Method.

Let's try to solve by using [ Elimination Method ]

$\tt \dagger \: \: \: \: \: 2x + 3y = 11.$

$\tt \dagger \: \: \: \: \: 2x - 4y = - 24.$

Subtract Equation ( 1 ) from ( 2 )

$\tt : \implies 3y + 4y = 11 + 24.$

$\tt : \implies 7y =35$

$\tt : \implies y = \dfrac{35}{5}$

$\tt : \implies y = 5.$

Now, putting the value of y in Equation ( 2 ) We get.

$\tt : \implies 2x - 4y = - 24.$

$\tt : \implies 2x - 4(5)= - 24.$

$\tt : \implies 2x - 20= - 24.$

$\tt : \implies 2x = - 24 + 20$

$\tt : \implies 2x = - 4$

$\tt : \implies x = - \dfrac{4}{2}$

$\tt : \implies x = - 2.$

Now, We need to find the value of m.

$\tt : \implies y= mx + 3.$

$\tt : \implies 5= m( - 2) + 3.$

$\tt : \implies 5 - 3= - 2m$

$\tt : \implies 2= - 2m$

$\tt : \implies m = - 1.$

Therefore, the value of m is - 1.