Question

3x + 5y = 78

2x - y = 0
The point of intersection of the lines has an x-coordinate of _____.
78
6
-6

Answer 1

Hello here is a solution :
3x + 5y = 78 .... (1)
2x - y = 0 ... (2)
from (2) : y = 2x
in (1) : 3x+5(2x) =78
13x = 78
x= 6
but : y =2x y=2(6) = 12
answer : x=6

Answer 2

Answer: The correct option is (B) 6.

Step-by-step explanation: We are given to select the x co-ordinate of the point of intersection of the following lines.

`3x+5y=78~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)\\\\2x-y=0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(ii)`

To find the x co-ordinate of the point of intersection, we need to solve the given system of equation to find the point of intersection.

From equation (ii), we have

`2x=y\\\\\Rightarrow y=2x~~~~~~~~~~~~~~~~~~~~~~~~(iii)`

Substituting the value of y from equation (iii) in equation (i), we get

`3x+5(2x)=78\\\\\Rightarrow 3x+10x=78\\\\\Rightarrow 13x=78\\\\\Rightarrow x=(78)/(13)\\\\\Rightarrow x=6.`

Thus, the x co-ordinate of the point of intersection of the given lines is 6.

Option (B) is CORRECT.