Question

Solve following simultaneously eqn 5x+2y=-3,x+5y=4

Answer 1

$x + 5y = 4 \\ x = 4 - 5y$

Substituting the value of x in another equation,

$5(4 - 5y) + 2y = -3 \\ 20 - 25y + 2y = -3 \\ - 23y = -23 \\ y = 1$

Substituting the value of y in the another equation,

$x = 4 - 5(1) \\ x = 4 - 5 \\x= -1$

Hence x = -1 & y = 1.

Answer 2

Answer:

5x + 2y = –3 .....(I)

x + 5y = 4 .....(II)

Multiply (II) with 5 we get

5x + 25y = 20 .....(III)

Subtracting (III) from (I) we get

5x−5x+2y−25y=−3−20

⇒−23y=−23

⇒y=−23−23=1

Putting the value of y = 1 in (II) we get

x+5(1)=4⇒x+5=4⇒x=4−5=−1

Thus, (x, y) = (−1, 1)