System of equations by graphing?

Question

Solve the system of equations by graphing

y=4x+4
y=-x-1

I have a graph with me...but I don't know where to put the coordinates...help plerz

Answer 1

The first equation is y = 4 x + 4.

Compare the equation with slope-intercept form y = m x + b, where m is slope and b is y-intercept.

slope = 4 and y-intercept is 4.

y-intercept is 4, so the line crosses the y-axis at origin (0, 4)

Using slope find the next point.

Slope = rise/run = 4/1

Start at point (0, 4), move 4 unit up and 1 unit right, then plot the point (1, 8).

The second equation is y = -x - 1.
Compare the equation with slope-intercept form y = m x + b, where m is slope and b is y-intercept.

slope = -1 and y-intercept is -1.

y-intercept is -1, so the line crosses the y-axis at origin (0, -1)

Using slope find the next point.

Slope = rise/run = -1/1

Start at point (0, -1), move 1 unit down and 1 unit right, then plot the point (1, -2).

Draw the lines through these points.

Graph :

Observe the graph, the solution of the system (x, y) = (- 1, 0).