Question

if 7x+10y=55 and 10x+ 7y=64 then x-y

Answer 1

The value for x-y is 3.

Given,

          7x+10y=55  (equation 1)

          10x+7y=64  (equation 2)

To find,

         Value of (x-y)

Solution,

         On subtracting equation 1 from equation 2, we get,

          3x-3y=9

          3(x-y)=9

          x-y= 3

Thus, the value of (x-y) is 3.

Answer 2

Answer:

if 7x+10y=55 and 10x+ 7y=64 then $x-y=3$

Step-by-step explanation:

We have two equations from which we need to find two variables say X and Y

The given equations are

$7x+10y=55$   (equation 1)

$10x+7y=64$   (equation 2)

to solve these equations we need the same coefficient for the same variables in two equations

to make the coefficients the same multiply the first equation with $10$ and second equation with $7$

⇒

$10(7x+10y=55)$$=70x+100y=550$ (equation 3)

$7(10x+7y=64)=70x+49y=448$ (equation 4)

now subtract equation 4 from equation 3

⇒

$51y=102\\y=102/51=2$

substitute the value of Y in equation 1 to get value of X

$7x+20=55\\\\7x=55-20=35\\x=35/7=5$

therefore $x-y=5-2=3$ which is the required answer