Question

srijan maths
q 11 b ii​

Answer 1

Step-by-step explanation:

Given equations are :

15/x+2/y=17-----(1)

1/x+1/y=36/5----(2)

Put 1/x=a ; 1/y=b then

=>15a+2b=17-----(3)

=>a+b=36/5------(4)×2

=>2a+2b=72/5----(5)

On solving (3)&(5)

15a+2b=17

2a+2b=72/5

(-)

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

13a+0=17-72/5

13a=(85-72)/5

13a=13/5

=>a=1/5

1/x=1/5

=>X=5

and from (4)

1/5+b=36/5

=>b=(36-1)/5

=>b=35/5

=>b=7

=>1/y=7

=>y=1/7

The Solution=(5,1/7)

Answer 2

Answer:

Question

$\to \frac{15}{x} + \frac{2}{y} =17 \: \: \: ......(1.) \\ \\ \to \frac{1}{x} + \frac{1}{y} = \frac{36}{5} \: \: \: .....(2.)$

Method !

➙ elimination method

Solution

➙ let us assume 1/x as a and 1/y as b.

so equations:

15 a +2b= 17. ......(1.)

1a+1b= 36/5. ......(2.)

Now multiply the second equation by 15

15 a + 2b= 17 ....(1.)

15 a+15 b= 108. ....(2.)

subtact the equations

15 a + 2b= 17

15 a+15 b= 108

(-). (-). ( -)

_______________

-13b= -91

b= 91/13

b= 7

b= 1/y = 7

so ...y = 7

Now substitute the value of y in any of the equation to find the value of x

value of x = 5

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