Intermediate Geometry : How to find the equation of a curve

Study concepts, example questions & explanations for Intermediate Geometry

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Example Questions

Example Question #1 :How To Find The Equation Of A Curve

If a line's-intercept is. and the-intercept is, what is the equation of the line?

Possible Answers:

Correct answer:

Explanation:

Write the equation in slope-intercept form:

We were given the-intercept,, which means:

Given the-intercept is, the point existing on the line is. Substitute this point into the slope-intercept equation and then solve forto find the slope:

Addto each side of the equation:

Divide each side of the equation by:

Substituting the value ofback into the slope-intercept equation, we get:

By subtractingon both sides, we can rearrange the equation to put it into standard form:

Example Question #2 :How To Find The Equation Of A Curve

Find the-intercept of:

Possible Answers:

Correct answer:

Explanation:

To find the x-intercept, we need to find the value ofwhen.

So we first setto zero.

turns into

Lets subtract两边移动to one side of the equation.

After doing the arithmetic, we have

.

Divide byfrom both sides

Example Question #1 :How To Find The Equation Of A Curve

What is the-intercept of:

Possible Answers:

Correct answer:

Explanation:

To find the y-intercept, we set

So

turns into

.

After doing the arithmetic we get

.

Example Question #1 :How To Find The Equation Of A Curve

What is the-intercept of:

Possible Answers:

Correct answer:

Explanation:

The x-intercept can be found where

So

turns into

.

Lets subtractfrom both sides to solve for.

After doing the arithmetic we have

.

Divide both sides by

Example Question #5 :How To Find The Equation Of A Curve

Suppose two intercepts create a line. If the-intercept isand-intercept is, what is the equation of the line?

Possible Answers:

Correct answer:

Explanation:

Rewrite the intercepts in terms of points.

X-intercept of 1:.

Y-intercept of 2:

Write the slope-intercept form for linear equations.

Substititute the y-intercept into the slope-intercept equation.

Substitute both the x-intercept point and the y-intercept into the equation to solve for slope.

Rewrite by substituting the values ofandinto the y-intercept form.

Example Question #6 :How To Find The Equation Of A Curve

Which equation has a y-intercept at 2 and x-intercepts at -1 and 6?

Possible Answers:

Correct answer:

Explanation:

In order for the equation to have x-intercepts at -1 and 6, it must haveandas factors. This leaves us with only 2 choices,or

This equation must also have a y-intercept of 2. This means that plugging in 0 for x will gives us a y-value of 2. Because we have two options, we could plug in 0 for x in each to see which gives us an answer of 2:

a)we can eliminate that choice

b)this must be the right choice.

If we hadn't been given multiple options, we could have set up the following equation to figure out the third factor:

divide by -6

Example Question #1 :How To Find The Equation Of A Curve

Which equation would have an x-intercept atand a y-intercept at?

Possible Answers:

Correct answer:

Explanation:

We're writing the equation for a line passing through the pointsand. Since we already know the y-intercept, we can figure out the slope of this line and then write a slope-intercept equation.

To determine the slope, divide the change in y by the change in x:

The equation for this line would be.

Example Question #8 :How To Find The Equation Of A Curve

Write the equation of a line with interceptsand

Possible Answers:

Correct answer:

Explanation:

The line will eventually be in the formwhereis the y-intercept.

The y-intercept in this case is.

To find the equation, plug infor, and the other point,as x and y:

addto both sides

This means the equation is

Example Question #9 :How To Find The Equation Of A Curve

Which equation has the x- and y-interceptsand?

Possible Answers:

Correct answer:

Explanation:
Since this line has the y-intercept, we know that in the form,
We can plug in the other intercept's coordinates forandto solve for:
subtract
divide by
The line is
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