160k views
3 votes
2x+y=1

9x + 3y = -3

The x-coordinate of the point of intersection is

-2
0
5

1 Answer

1 vote

Answer:

The x-coordinate of the point of intersection is -2

Explanation:

Here we have a typical system of linear equations whose solution will give us both the x- and the y- coordinates (i.e. the intersection point).

Let us solve the system and find which matches the available options, as follow. Given:


2x+y=1\\9x+3y=-3

Taking the first expression and re arranging to solve for
x we have:


2x+y=1\\2x=1-y\\x=(1-y)/(2) Eqn.(1)

Plugging in it, in the second expression we then have


9((1-y)/(2) )+3y=-3\\\\(9)/(2)-(9y)/(2)+3y=-3\\ \\(9)/(2)-(9y)/(2)+(6y)/(2)=-(6)/(2)\\ \\-(9y)/(2)+(6y)/(2)=-(6)/(2)-(9)/(2)\\-3y=-15\\y=(-15)/(-3)\\ y=5

So finally plugging in the y value in Eqn.(1) we have


x=(1-5)/(2) \\x=(-4)/(2)\\ x=-2

The x-coordinate of the point of intersection is -2

User Augusto Destrero
by
8.7k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories