Need help understanding solving linear equations graphically

I have to solve the following problem both algebraically and graphically -

A person cuts a rope into two pieces that are equal in length. The first piece is 4 times the length of the person’s forearm minus 1 inch. The second piece is 3 times the length of the person’s forearm plus 15 inches.

My algebraic equation for this is - 4x-1 = 3x+15

I just don't understand how to graph this equation out. I would appreciate any help I can get with this simple problem.

At a guess (and I'm only guessing, since I'm not in your class, so I haven't seen the examples done in class, nor can I read the examples done in your text), you are intended to turn each half of your one-variable algebraic equation into the right-hand sides of two-variable line equations.

For instance, one could solve "x + 5 = -2x + 6" by moving the 2x to the left-hand side, the 5 to the right-hand side, and dividing through by 3 (that is, one could solve this algebraically). Or one could solve "graphically", by graphing y = x + 5 and y = -2x + 6, and finding where the lines cross. Of course, to be sure of the guess from the graph, you'd end up having to solve algebraically anyway....

Eliz.

zjb0417 said:

I have to solve the following problem both algebraically and graphically -

A person cuts a rope into two pieces that are equal in length. The first piece is 4 times the length of the person’s forearm minus 1 inch. The second piece is 3 times the length of the person’s forearm plus 15 inches.

My algebraic equation for this is - 4x-1 = 3x+15

I just don't understand how to graph this equation out. I would appreciate any help I can get with this simple problem.

Click to expand...

To solve graphicallt - ploy:

y = 4x - 1

and

y = 3x + 15

The point of intersection will give you the solution.