Question

Consider this system of two linear equations.

5x − 2y = 16
-4x + 6y = -15
What is the y-coordinate of the solution to the system of equations?

A. 1/3
B. 15
C. -1/2
D. 3

Answer 1

Explanation:

so these two lines cross at some point.. and they want to know the y point at which they cross... sooo..

solve them as a system to find the points that are common to both

Eq. 1) 5x -2y = 16

Eq. 2) -4x+6y=-15

i'll use the elimination method as these equations "lend" themselves to that way.. they are easy to solve that way .. in other words..

multiply Eq. 1 by 3 the add Eq. 2 .. to it... add the terms as columns....

15x-6y = 48

+ ( -4x+6y=-15)

= 11x+ 0y =33

x=3

nice, now plug 3 in for x in one of the Eq. try Eq. 1

5(3)-2y=16

15-2y=16

-2y =1

y =
`-(1)/(2)`

since we're looking for the y coordinate... that's your answer
`-(1)/(2)`