Subject: algebra 1
Name: jennifer
Who are you: Parent (Secondary)

I am having problems explaining how to do these problems to my child .

graph:2=x-y

graph the equation: 2y+x=-3

can you please help me.

Hi Jennifer,

I'll look at the second problem.

I would start by plotting two special points.

First let x = 0 then since 2y + x = -3, when x = 0,

2y + 0 = -3 and hence y = ^-3/₂ .

Thus the point x = 0, y = ^-3/₂, in other words the point (0,  ^-3/₂ ) is on the graph.

For the second point let y = 0. Then since 2y + x = -3, when y = 0,

0 + x = -3 and hence x = -3.

Thus (-3, 0) is on the graph also.

Now plot more points,

when x = 1, 2y + x = -3 so 2y + 1 = -3 and hence y = -2
when x = -1, 2y + x = -3 so 2y + -1 = -3 and hence y = -1
when x = 2, 2y + x = -3 so 2y + 2 = -3 and hence y = ^-5/₂ 

As you plot more points you can see that they all lie on a straight line and this line is the graph of the equation 2y + x = -3.

Now try the other problem.
Penny