Question

Which value of x satisfies both 3x + y = 9 and 3x − 5y = 15?. A) \[\frac{ 10 }{ 3 }\]. B) \[\frac{ 2 }{ 3 }\]. C) \[-1\]. D) \[0\].

Answer 1

Option A. is the correct option.

Explanation:

Two equations are 3x + y = 9 ------------(1)

and 3x - 5y = 15 ----------(2)

we have to calculate the value of x common for both.

We multiply equation 1 by 5 and add it to equation 2

15x + 5y = 45

3x - 5y = 15___

18x = 60

x =
`(60)/(18)=(10)/(3)`

Therefore option A.
`x=(10)/(3)` is the answer.

Answer 2

Multiply the first equation by five to yield, 15x + 5y = 45. Add this equation to the second equation from the given,
15x + 5y = 45
+ 3x - 5y = 15
The answer would be 18x = 60. The value of x is 10/3. Therefore, the answer to this item is letter A.