Answer:

a. 3

Step-by-step explanation:

To solve this system of equations:

31x + 47y = 15

47x + 31y = 63

We can use the method of elimination. Multiplying the first equation by 47 and the second equation by -31, we get:

1457x + 2209y = 705

-1457x - 961y = -1953

Adding these two equations together, we get:

1248y = -1248

Dividing both sides by 1248, we get:

y = -1

Substituting y = -1 into either of the original equations, we get:

31x + 47(-1) = 15

31x - 47 = 15

31x = 62

x = 2

Therefore, x - y = 3.

So the answer is (a) 3.

I hope that helps!

Verified answer

On solving 31x+47y= 15 and 47x+31y = 63, then x-y= a) 3. b)-3. c) 1/3. d)-1/3.

Step-by-step explanation:

47x+31y63 ---(i)

31 +47y 15(ii)

multiplying (i) by 31 and multiplying (ii) by 47 we

get

1457x+961y 1953 (iii)

1457x+2209y= 705 ---(iv)

subtracting (iv) from (iii) we get -1248y 1248

⇒y=-1 putting y=-1 in (i)

47x+31x-1= 63

47 94 ⇒ 47x=

x 2 and y = -1