Question

solve the LE : x+3y=10 and 2x-y+1=0 . Hence find the value of 'p' if x+py=7 .​

Answer 1

Answer:

The value p in x + py = 7 is 2.

Step-by-step explanation:

Given two linear equations in two variables :

☞ x + 3y = 10 . . . . . (1)

☞ 2x – y = – 1 . . . . . (2)

Getting the value of x from (1) :

☞ x + 3y = 10

☞ x = 10 – 3y . . . . . . (3)

Substituting this value of x in (2) :

☞ 2x – y = – 1

☞ 2 ( 10 – 3y ) – y = – 1

☞ 20 – 6y – y = – 1

☞ 20 – 7y = – 1

☞ – 7y = – 1 – 20

☞ – 7y = – 21

☞ y = – 21/– 7

☞ y = 3

Substituting this value of y in (1) to get x :

☞ x + 3y = 10

☞ x + 3 ( 3 ) = 10

☞ x + 9 = 10

☞ x = 10 – 9

☞ x = 1

Therefore, the values of x and y in the system of linear equations x + 3y = 10 and 2x – y = – 1 are 1 and 3 respectively.

Now, substituting these values in x + py = 7 to get p :

☞ x + py = 7

☞ 1 + p ( 3 ) = 7

☞ 1 + 3p = 7

☞ 3p = 7 – 1

☞ 3p = 6

☞ p = 6/3

☞ p = 2

Therefore, the value of p in x + py = 7 is 2.