Here's the question you clicked on:
manamesasher
Solve the following system of equations graphically, find the graph 2x -y = -1 x + y = -2
Easiest way to do this is to plug in the point of intersection and if both equations are true, then it's the correct answer. For instance, let's check 2. \[2x - y = -1\]\[2(1) - (-1) = -1\]\[2 + 1 = -1\]\[3 ≠ -1\]THerefore, it isn't 2.
i was talking about the graph...
Also, if the point of intersection is the same in two choices, then you have to make sure the lines make sense.
And yes, 2 is incorrect since the solution set is also the point of intersection when graphed...
Are you just guessing at this point?
no i'm asking if you can help me solve it...
Alright. I explained the process above... Let's take a look at choice 3... 2x - y = -1 Plus in the point of intersection, (-1, 1) 2(-1) - (1) = -1 -2 - 1 = -1 -3 ≠ -1 Do you see how the final equations ends up false since -3 does NOT equal -1?
ok. and choice 1, (-1, -1) 2(-1)-(-1)=-1
so it is choice 1..
my idea would be to use a knowledge of the equations to match the graph in this manner x + y = -2 notice this is pretty easy to turn to y = mx+b format y = -x-2 we need to find an option that has a line going thru y=-2 and a downill slope of -1
Um... \[2(-1) - (-1) = -1\]\[-2 + 1 = -1\]\[-1 = -1\]You should always check both equations by the way for the future, but it is indeed choice 1 :)
oh, ok sorry.. thanks again...
1 and 3 fit the thru -2 part; and 3 is too steep for comfort