Question

Solve the system by using substitution

4y = x
3x - y = 70

A) (2 2/3, 1 1/3)

B) (25 5/11, 6 4/11)

C) (35, 8 3/4)

D) (6 4/11, 25 5/11)

Please help and explain!!

Answer 1

Option B is the answer of the required system

Explanation:

As given to us that

4y = x let it be equation (i)

and

3x - y = 70 let it be equation (ii)

Now from equation (i) we see that

x = 4y .................(iii)

Putting this value in equation (ii)

We will get

3(4y)-y=70

12y - y = 70

11 y = 70

or

y =
`(70)/(11)` ...................(iv)

Putting this in equation (iii)

Now it becomes

x = 4*
`(70)/(11)`

or

x=
`(280)/(11)`

AS the answer given to us are in mixed fractions so we will do the division of it

First for y

y =
`(70)/(11)`

Actually in the division we calculate the table of Divisor which is 11 to get a remainder and an answer

Now when we will calculate the table of 11 we see that

11 * 6 = 66

and 11 * 7 = 77

As 70 is smaller then 77 so

When we will do the division of 70 with 11

Quotient is 6 Remainder is 4 and divisor is 11

And it can be written in the form of Mixed fraction as

Answer = Quotient *
`(Remainder)/(Divisor)`

So

y = 6*
`(4)/(11)`

Now similarly for value of x

When we will do the division of 280 with 11

Quotient is 25 Remainder is 5 and divisor is 11

And it can be written in the form of Mixed fraction as

x = 25*
`(5)/(11)`

So Answer will be option B