I really need help with my math homework!!

Tutors, sign in to answer this question.

Emma, the answers above all provide some different ways to help you understand the question you asked. You had to use both your math knowledge and critical thinking skills to arrive at the right solution. Now you should be ready to move on the new challenges!

If you would like a tutor in Brevard, NC, so that you can ask questions like this regularly and get support when you hit problem areas in math and other subjects, look up my profile and drop me a note.

Warmest regards in this new year!

~ Kevin

Emma,

The standard equation for a line is :

y = ax + b

y is called the dependent variable because its value depends on the value of x

a is the slope of the line

x is called the independent variable because it can be any value

b is the y-intercept

In your case : y(x) = 5x, y(x) is just another way of writing the equation to indicate that y is a function of x. You could simply write it as y = 5x. Thus if we compare to the standard form equation y = ax + b, a=5 and b=0. Thus the y-inercept is zero. The reason that this is the case is that when you set x=0 the value is plotted on the y axis, because the equation for the y axis is the line defined by x=0. Any value in the x,y plane where x is equal to zero plots on the vertical line going through (0,0) or in other words the y axis.

The x-intercept is a little harder to find. We have to set y=0 as that is the line defining the x axis. We start with the original equation. y = ax + b. Setting y=0 gives ax+b = 0. Subtracting b from both sides gives ax = -b. Finally dividing both sides by a yields the x-intercept, x = -b/a.

From above for y=5x, a=5 and b=0, the the x-intercept would be -0/5 which is also 0. So when b=0 the line goes through (0,0) otherwise known as the origin.

Hi Emma,

If we are given a function where the "y" value depends on the "x" value, the y-intercept (where the function crosses the y-axis) is simply the y-value when x=0, because at the y-axis, x=0.

(y, as a function of x) y(x) = 5x

y(0) = 5(0) (the function value, with "0" plugged in for the "x" value)

y(0)=0

So the y-intercept is 0. This function crosses the y-axis at a y value of 0.

The y-intercept is the value of y when x=0

Emma, think of this as being in the form y = mx + b, where m is the slope and b is the y-intercept.

Because there is no b in the equation, then b = 0. We just don't write y = 5x + 0.

Already have an account? Log in

By signing up, I agree to Wyzant’s terms of use and privacy policy.

Or

To present the tutors that are the best fit for you, we’ll need your ZIP code.

Your Facebook email address is associated with a Wyzant tutor account. Please use a different email address to create a new student account.

Good news! It looks like you already have an account registered with the email address **you provided**.

It looks like this is your first time here. Welcome!

To present the tutors that are the best fit for you, we’ll need your ZIP code.

Please try again, our system had a problem processing your request.