solving systems by graphing 9 grade?

to plot the lines all u need is 2 pairs of points on each line.

Why ? your eqn are straight lines; for this to be false the highest power of x should be > 1

easiest way to find points is to give 0 values to x and y respectively and find its corresponding pair

eg. 1.) 3x + y =10

x = 0 => y = -10 ==> A(0,-10)

y = 0 => x = -10/3 ==> B(-3.3333, 0)

and so on

by plotting the lines, u should easily spot the points where ALL 4 lines meet

1) there is no solution. The 2 lines run parallel to each other (same slope, different y intercept), so they will never cross

2) there are infinite solutions. The 2 lines are the same line (same slope and y intercept), so they run on top of each other, making every point on the line the right answer.

http://i44.tinypic.com/1zdyrlg.jpg

that's the graphed solution.

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