Lines and linear functions

Linear equations in two variables, including horizontal and vertical lines

Graph equations in two variables and recognize slope, intercepts, horizontal lines, and vertical lines.

283 questions Foundation to advanced Grade 9

Concept overview

A linear equation in x and y represents a straight line. The form y = mx + b shows slope and y-intercept directly, while x = a is a vertical line and y = b is a horizontal line.

Key points

  • Horizontal lines have slope 0 and equations of the form y = constant.
  • Vertical lines have undefined slope and equations of the form x = constant.
  • A pair (x, y) is a solution when substitution makes the equation true.

Worked example

The equation x = −3 is a vertical line through every point whose x-coordinate is −3. The equation y = 4 is horizontal and crosses the y-axis at 4.

Try it free

Answer a few questions without signing in. You will get instant feedback, but open-preview progress is not saved.

0 / 5

Questions by difficulty

115foundation
108medium
60advanced

Linear equations in two variables worksheet practice

Use the printable worksheet for independent practice, then check the answer key and worked explanations.

Open worksheet with answers

Frequently asked questions

How should I practice Linear equations in two variables?

Start with foundation questions, check each answer, and move up a level after several correct answers in a row.

How many practice questions are available?

IQClub currently has 283 published questions for this skill.

Can I use this for test preparation?

Yes. The practice reinforces school mathematics and the same reasoning used in high-school tests and entrance exams.

SAT® is a registered trademark of the College Board. ACT® is a registered trademark of ACT, Inc. PSAT/NMSQT® is a registered trademark of the College Board and the National Merit Scholarship Corporation. AP®, Advanced Placement Program®, and Pre-AP® are registered trademarks of the College Board. IQClub.com is not affiliated with, endorsed by, or sponsored by any of these organizations.