Question

x+y=4 ; 2x–5y=1, Solve the set of simultaneous equations.

Answer 1

Answer:

x = 3

y = 1

Step-by-step explanation:

In the question

The given equations are

x + y = 4                    .........(i)

2x - 5y = 1                 ..........(ii)

from equation (i)

x + y = 4

x = 4 - y

Put the value of x in equation (ii)

2(4 - y) -5y = 1

8 - 2y - 5y = 1

- 7y = 1 - 8

- 7y = - 7

y = 1

Now put the value of y in equation (i)

x + 1 = 4

x = 4 - 1

x = 3

Hence, the solution will be x = 3 and y = 1.

Answer 2

Answer:

x = 3

y = 1

Step-by-step explanation:

x + y = 4 ...........( i )

2x - 5y = 1 ........( ii )

Multiplying equation ( i ) by 5

.°. 5x + 5y = 20 ..............( iii )

Adding equation ( ii ) and equation ( iii )

.°. 5x + 5y = 20

+2x - 5y = 1

-----------------------

7x = 21

x = 21/7

.°. x = 3

Substituting the value of x in equation ( i )

x + y = 4

.°. 3 + y = 4

.°. y = 4 - 3

.°. y = 1