Question

if (k-2,5k) are the solution of the equation 3x+4y=9 then find k

Answer 1

Answer:

The question is from ratio and proportion and we have got 2 methods to solve it. Either we get the value of one variable in terms of the other or we take their values w.r.t some third variable.

First I'll use the second method as I find it rather less calculative and thus it helps in avoiding mistakes. So here it goes -

x:y=3:5

Now we introduce a third variable ‘a’ and we'll find the values of x and y w.r.t a

So, let x=3a and y=5a

Now applying this value of x and y in the given ratio we get

3x+4y:8x+5y

=3(3a)+4(5a):8(3a)+5(5a)

=9a+20a:24a+25a

=29a:49a

=29:49

So the answer is 29:49

Now I'm gonna solve it using the first method. This method needs to be carried out carefully as calculation mistakes are common due to mathematical operations involving fractions.

x:y=3:5

x=3y/5

Applying this in the equation we get

3x+4y:8x+5y

=3(3y/5)+4y:8(3y/5)+5y

=9y/5+4y:24y/55y

=y(9+20)/5:y(24+25)/5

Since both have y and 5 multiplied and divided to it so we can remove them.

So the answer is

Answer 2

Answer:

15/23

Step-by-step explanation:

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