anonymous 5 years ago blue line is Y=x/2 -1 and green line is Y=2x+1 where do the lines cross ?

1. nice

Y = Y x/2 -1 = 2x+1 2x-x/2=-1-1 3x/2 = -2 3x = -4 x = -4/3

2. mathteacher1729

The lines cross where the two equations are equal: $\frac{x}{2}-1=2x+1$ Can you solve that equation? Also, have you tried graphing these lines with geogebra or your calculator?

3. nice

put that x = -4/3 in any equation to get y comp.

4. anonymous

Let. blue line=red line Y=Y x/2-1=2x+1 x/2=2x+2 x=4x+4 x-4x=4 -3x=4 x=-4/3\ Answer=-4/3

5. mathteacher1729

Here is the graph.

6. mathteacher1729

You can create that graph by going to http://www.wolframalpha.com and typing in "plot y = x/2 -1 and y = 2x+1" (without the quotes).

7. anonymous

thanks for the help !