X and Y Intercepts

Greg WindleAlgebra 2C

What is the X-Intercept?

• The value of X when the line or curve of a graph intersects or crosses the x axis.

What is the Y-Intercept?

• The value of Y when the line or curve of a graph intersects or crosses the Y axis.

Common Uses

• You will most commonly find the Y intercept in Algebra.

• This is found in the formula for a linear line: y=mx+b

• However the X incept can also be found using that formula.

Y = mx + b• Y = the y coordinate• M = Slope• X = the x coordinate• B = Y-intercept• In order to find the Y-intercept, you can simply

plug in the slope and one set of coordinates, and solve for b.

• There is no variable representing the x-intercept, however the x intercept is the coordinate of x when y is equal to 0. So plug in 0 for y, and solve for x in order to find the X-intercept.

EF-4 (a) y = -2x + 7

• The problem asks for you to graph this equation.

• One thing that all linear lines and equations have is a y-intercept, or b. In this case b=7

• So the y intercept is 7.• Plug in 0 for Y and solve for x.

The X-intercept of BB-4 (a)

• After you plug in 0 for y you should get this: 0 = -2x + 7.

• Subtract 7 from both sides: -7 = -2x• Divide both sides by -2: 3.5 = x• Therefore: When y is 0, x is 3.5• Making 3.5 the X-intercept.