How do you solve and graph y equals -2x plus 7?

Answer 1

y = -2x + 7 is already solved in terms of y. You can solve in terms of x (i.e., make x equal something):

y = -2x + 7

y - 7 = -2x

-y/2 + 7/2 = x

x = -y/2 + 7/2

but because there are two variables and only one equation, x (or y, for that matter) does not equal just one number.

There are several methods you can use to graph this linear equation. My favorite is plotting two points and drawing a straight line between them. To find a point on the graph, plug some number in for x and solve. For example, when x is 0,

y = -2x + 7

y = -2(0) + 7

y = 7.

So when x=0, y=7. You can plot the point (0,7) on your 2D plane. Similarly, when x =1, y = 5. Plot the point (1, 5) on your 2D plane. Because this is a linear equation, you can draw a straight line that hits both of these points.