79.0k views
5 votes
Need help please help me

Need help please help me-example-1
User HMR
by
8.1k points

2 Answers

2 votes

y = mx + b - it's the equation of a straight line. We need only two points to the plotting the graph of that function.

Select any two x values and calculate y values:


y=(1)/(2)x+2\\\\for\ x=0\to y=(1)/(2)(0)+2=0+2=0\to(0,\ 2)\\\\for\ x=-4\to y=(1)/(2)(-4)=-2+2=0\to(-4,\ 0)


y=x+5\\\\for\ x=0\to y=0+5=5\to(0,\ 5)\\\\for\ x=-5\to y=-5+5=0\to(-5,\ 0)

Look at the picture.

The solution of the system of equations is the intersection point of the line.

Answer: (-6, -1) → x = -6 and y = -1


Need help please help me-example-1
User Florie
by
8.1k points
2 votes
The solution is the point of intersection between the two equations.

Assuming you have a graphing calculator or a program to lets you graph equations (I use desmos) you simply put in the equetions and note down the coordinates of the point of intersection.

In the graph the first equation is in blue and the second in red.

The point of intersection = the solution = (-6 , -1)



If you dont have access to a graphing calculator you could draw the graphs by hand;

1) Draw a table of values for each equation; you do this by setting three or four values for x and calculating its image in y (you can use any values of x)

y = 0.5 x + 2 (Im writing 0.5 instead of 1/2 because I find its easier in this format)

x | y
-1 | 1.5 * y = 0.5 (-1) + 2 = 1.5
0 | 2 * y = 0.5 (0) + 2 = 2
1 | 2.5 * y = 0.5 (1) + 2 = 2.5
2 | 3 * y = 0.5 (2) + 2 = 3

y = x + 5

x | y
-1 | 4 * y = (-1) + 5 = 4
0 | 5 * y = (0) + 5 = 5
1 | 6 * y = (1) + 5 = 6
2 | 7 * y = (2) + 5 = 7

2) Plot these point on the graph
I suggest to use diffrent colored points or diffrent kinds of point markers (an x or a dot) to avoid confusion about which point belongs to which graph

3) Using a ruler draw a line connection all the dots of one graph and do the same for the other

4) The point of intersection is the solution
Need help please help me-example-1
User IssamTP
by
8.7k points