Math CentralQuandaries & Queries


Question from jenn, a parent:

change the equation,x-y=4 to form y=mx+b

the solution to the system of equations y=2x and y=-x+3 is ?

Hi Jenn.

For the first question, just remember that "m" and "b" are actually numbers. For example, y = -x + 17 is in the form y = mx + b, and the m is -1 (the 1 is implied if there are no digits in front of the x) and the b is 17.

For the second question, you need to realize that if y = something and also y = another thing, then the something = the other thing.

So in your question, 2x = -x + 3. Solve for x and find the number x equals. Then use that in either one of the equations to replace x (so you just have an equation with y in it). Then solve for y. The two values of x and y are the "solution" to the system.

Stephen La Rocque.

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