Question

Solve the following linear equations by elimination method:3x –y - 7=0, 2x+5y= -1

Answer 1

Step-by-step explanation:

3x-y =7

2x+5y=-1

multiply eq. 1 by 2 and eq. 2 by 3

then

6x-2y=14

6x+15y=-3

subtract the eq.

17y=-17

y=-1

x=2

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Answer 2

AnsWer :

• x = 2.
• y = - 1.

GiveN :

• We have Equation,
• 3x – y - 7 = 0, 2x + 5y = - 1.

SolutioN :

$\tt\dagger \: \: \: \: \: 3x - y - 7= 0. \: \: \: \: \: - (1)$

$\tt\dagger \: \: \: \: \: 2x + 5y + 1= 0. \: \: \: \: \: - (2)$

A/Q,

We have,

• Elimination method.
• Substitution method.
• Cross multiplication method.

Note : Elimination Method ( attached above )

★ Let' s try to solve by substitution method.

Taking Equation ( 1 )

$\tt : \implies 3x - y - 7 = 0.$

$\tt : \implies 3x - 7 = y. \: \: \: \: \: - (3)$

Now, Putting the value of y in Equation, ( 2 )

$\tt : \implies 2x + 5y + 1 = 0.$

$\tt : \implies 2x + 5(3x - 7) + 1 = 0.$

$\tt : \implies 2x + 15x - 35 + 1 = 0.$

$\tt : \implies 17x - 34 = 0.$

$\tt : \implies x = \dfrac{34}{17} .$

$\tt : \implies x = 2.$

Now, Putting the Value of x in Equation, ( 3 ) We get,

$\tt : \implies y = 3x - 7.$

$\tt : \implies y = 3(2)- 7.$

$\tt : \implies y = 6 - 7.$

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

Verification :

Taking Equation ( 1 )

$\tt : \implies 3x - y - 7 = 0.$

$\tt : \implies 3(2) - ( - 1) - 7 = 0.$

$\tt : \implies 6 + 1 - 7 = 0.$

$\tt : \implies 7 - 7 = 0.$

$\tt : \implies 0 = 0.$

# Hence Verify.