Solve the system of linear equations by graphing. y = –x – 7 x + 2y = 4 What is the solution to the system of linear equations? (–4.5, 4.25) (–1.7, –2.8) (0, –7) (3, 0.5)

Question

asked Jun 13, 2020 53.4k views

2 Answers

Zhenlan Wang · Answer 1 · 2020-06-16T02:26:53+0000

For this case we have the following system of equations:

$y = -x-7\\x+2y = 4$

Substituting the first equation in the second one we have:

$x+2 (-x-7) = 4\\x-2x-14 = 4\\-x = 4 14\\-x = 18\\x = -18$

We find the value of y:

$y = - (- 18) -7\\y = 18-7\\y = 11$

Thus, the solution of the system is:

(-18,11)

Answer:

(-18,11)

Martin Kristiansen · Answer 2 · 2020-06-18T12:22:55+0000

Answer: (-18,11)

Explanation:

Find the x-intercept of the first equation by substituting
y=0 and solving for "x":

$y = -x - 7\\\\x=-7$

Find the y-intercept of the first equation by substituting
x=0 and solving for "y":

$y = -x - 7\\\\y=0-7+\\\\y=-7$

Graph the line passing through the points (-7,0) and (0,-7)

Find the x-intercept of the second equation by substituting
y=0 and solving for "x":

$x + 2y = 4\\\\x + 2(0) = 4\\\\x=4$

Find the y-intercept of the second equation by substituting
x=0 and solving for "y":

$x + 2y = 4\\\\0 + 2y = 4\\\\y=2$

Graph the line passing through the points (4,0) and (0,2)

You can observe in the graph that the point of intersection of the lines is:

(-18,11)

This is the solution of the system of equations.