Question

from 87x + 53y =15 and 53x +87y = -155 then x-y is ___________

Answer 1

Answer:

371.13

Step-by-step explanation:

We have been given that

$87x+53y=15\\53x+87y=-155$

Calculate the value of x and y from the given equation by using elimination method:

firstly we arrange the equation so that we cancel out the same

$4611x+7569y=13,485------(i)\\4611x+2809y=795------(ii)$

Substitute the equation (ii) from the equation (i)

$4760y=12690\\y=\frac{12690}{4760}\\ y=2.67$

Substitute the value of y in equation

$87x+53y=15\\87(2.67)+53(2.67)=15\\232.29+141.51=15\\373.8$

Find the x-y....

$x-y=373.8-2.67=371.13$

Thus,the value of x-y is 371.13.

Answer 2

Answer:

Step-by-step explanation:

87x + 53y = 15       ---------1

53x + 87y = -155    --------2

on subtracting equation 2 from 1, we get

34x - 34y = 170

∴ x - y = 5    ---------A

on adding equation 1 and 2, we get

140x + 140 y = -140

∴ x + y = -1      ----------B

on adding equation A and B, we get

2x = 4

∴ x = 2

on putting the value of x in equation B, we get

y = -3

∴ x - y = 2-(-3)

= 2 + 3

= 5

∴ correct answer is 5.